diff --git a/models/asymkey/gpg_key.go b/models/asymkey/gpg_key.go
index 1da7c346de..421f24d4de 100644
--- a/models/asymkey/gpg_key.go
+++ b/models/asymkey/gpg_key.go
@@ -92,10 +92,9 @@ func CountUserGPGKeys(ctx context.Context, userID int64) (int64, error) {
 	return db.GetEngine(ctx).Where("owner_id=? AND primary_key_id=''", userID).Count(&GPGKey{})
 }
 
-// GetGPGKeyByID returns public key by given ID.
-func GetGPGKeyByID(ctx context.Context, keyID int64) (*GPGKey, error) {
+func GetGPGKeyForUserByID(ctx context.Context, ownerID, keyID int64) (*GPGKey, error) {
 	key := new(GPGKey)
-	has, err := db.GetEngine(ctx).ID(keyID).Get(key)
+	has, err := db.GetEngine(ctx).Where("id=? AND owner_id=?", keyID, ownerID).Get(key)
 	if err != nil {
 		return nil, err
 	} else if !has {
@@ -225,7 +224,7 @@ func deleteGPGKey(ctx context.Context, keyID string) (int64, error) {
 
 // DeleteGPGKey deletes GPG key information in database.
 func DeleteGPGKey(ctx context.Context, doer *user_model.User, id int64) (err error) {
-	key, err := GetGPGKeyByID(ctx, id)
+	key, err := GetGPGKeyForUserByID(ctx, doer.ID, id)
 	if err != nil {
 		if IsErrGPGKeyNotExist(err) {
 			return nil
@@ -233,11 +232,6 @@ func DeleteGPGKey(ctx context.Context, doer *user_model.User, id int64) (err err
 		return fmt.Errorf("GetPublicKeyByID: %w", err)
 	}
 
-	// Check if user has access to delete this key.
-	if !doer.IsAdmin && doer.ID != key.OwnerID {
-		return ErrGPGKeyAccessDenied{doer.ID, key.ID}
-	}
-
 	ctx, committer, err := db.TxContext(ctx)
 	if err != nil {
 		return err
diff --git a/models/fixtures/comment.yml b/models/fixtures/comment.yml
index bd64680c8c..17586caa21 100644
--- a/models/fixtures/comment.yml
+++ b/models/fixtures/comment.yml
@@ -66,3 +66,12 @@
   tree_path: "README.md"
   created_unix: 946684812
   invalidated: true
+
+-
+  id: 8
+  type: 0 # comment
+  poster_id: 2
+  issue_id: 4 # in repo_id 2
+  content: "comment in private pository"
+  created_unix: 946684811
+  updated_unix: 946684811
diff --git a/models/fixtures/issue.yml b/models/fixtures/issue.yml
index ccc1fe41fb..0c9b6ff406 100644
--- a/models/fixtures/issue.yml
+++ b/models/fixtures/issue.yml
@@ -61,7 +61,7 @@
   priority: 0
   is_closed: true
   is_pull: false
-  num_comments: 0
+  num_comments: 1
   created_unix: 946684830
   updated_unix: 978307200
   is_locked: false
diff --git a/models/issues/comment.go b/models/issues/comment.go
index a59fa570af..ba5aed9c65 100644
--- a/models/issues/comment.go
+++ b/models/issues/comment.go
@@ -1024,6 +1024,7 @@ type FindCommentsOptions struct {
 	Type        CommentType
 	IssueIDs    []int64
 	Invalidated util.OptionalBool
+	IsPull      util.OptionalBool
 }
 
 // ToConds implements FindOptions interface
@@ -1058,6 +1059,9 @@ func (opts FindCommentsOptions) ToConds() builder.Cond {
 	if !opts.Invalidated.IsNone() {
 		cond = cond.And(builder.Eq{"comment.invalidated": opts.Invalidated.IsTrue()})
 	}
+	if opts.IsPull != util.OptionalBoolNone {
+		cond = cond.And(builder.Eq{"issue.is_pull": opts.IsPull.IsTrue()})
+	}
 	return cond
 }
 
@@ -1065,7 +1069,7 @@ func (opts FindCommentsOptions) ToConds() builder.Cond {
 func FindComments(ctx context.Context, opts *FindCommentsOptions) (CommentList, error) {
 	comments := make([]*Comment, 0, 10)
 	sess := db.GetEngine(ctx).Where(opts.ToConds())
-	if opts.RepoID > 0 {
+	if opts.RepoID > 0 || opts.IsPull != util.OptionalBoolNone {
 		sess.Join("INNER", "issue", "issue.id = comment.issue_id")
 	}
 
diff --git a/models/issues/content_history.go b/models/issues/content_history.go
index cc06b184d7..8c333bc6dd 100644
--- a/models/issues/content_history.go
+++ b/models/issues/content_history.go
@@ -218,9 +218,9 @@ func GetIssueContentHistoryByID(dbCtx context.Context, id int64) (*ContentHistor
 }
 
 // GetIssueContentHistoryAndPrev get a history and the previous non-deleted history (to compare)
-func GetIssueContentHistoryAndPrev(dbCtx context.Context, id int64) (history, prevHistory *ContentHistory, err error) {
+func GetIssueContentHistoryAndPrev(dbCtx context.Context, issueID, id int64) (history, prevHistory *ContentHistory, err error) {
 	history = &ContentHistory{}
-	has, err := db.GetEngine(dbCtx).ID(id).Get(history)
+	has, err := db.GetEngine(dbCtx).Where("id=? AND issue_id=?", id, issueID).Get(history)
 	if err != nil {
 		log.Error("failed to get issue content history %v. err=%v", id, err)
 		return nil, nil, err
diff --git a/models/issues/content_history_test.go b/models/issues/content_history_test.go
index 53638e967f..0ea1d0f7b2 100644
--- a/models/issues/content_history_test.go
+++ b/models/issues/content_history_test.go
@@ -58,13 +58,13 @@ func TestContentHistory(t *testing.T) {
 	hasHistory2, _ := issues_model.HasIssueContentHistory(dbCtx, 10, 1)
 	assert.False(t, hasHistory2)
 
-	h6, h6Prev, _ := issues_model.GetIssueContentHistoryAndPrev(dbCtx, 6)
+	h6, h6Prev, _ := issues_model.GetIssueContentHistoryAndPrev(dbCtx, 10, 6)
 	assert.EqualValues(t, 6, h6.ID)
 	assert.EqualValues(t, 5, h6Prev.ID)
 
 	// soft-delete
 	_ = issues_model.SoftDeleteIssueContentHistory(dbCtx, 5)
-	h6, h6Prev, _ = issues_model.GetIssueContentHistoryAndPrev(dbCtx, 6)
+	h6, h6Prev, _ = issues_model.GetIssueContentHistoryAndPrev(dbCtx, 10, 6)
 	assert.EqualValues(t, 6, h6.ID)
 	assert.EqualValues(t, 4, h6Prev.ID)
 
diff --git a/models/project/project.go b/models/project/project.go
index becfcbea1e..d2fca6cdc8 100644
--- a/models/project/project.go
+++ b/models/project/project.go
@@ -294,6 +294,18 @@ func GetProjectByID(ctx context.Context, id int64) (*Project, error) {
 	return p, nil
 }
 
+// GetProjectForRepoByID returns the projects in a repository
+func GetProjectForRepoByID(ctx context.Context, repoID, id int64) (*Project, error) {
+	p := new(Project)
+	has, err := db.GetEngine(ctx).Where("id=? AND repo_id=?", id, repoID).Get(p)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrProjectNotExist{ID: id}
+	}
+	return p, nil
+}
+
 // UpdateProject updates project properties
 func UpdateProject(ctx context.Context, p *Project) error {
 	if !IsCardTypeValid(p.CardType) {
diff --git a/models/repo/release.go b/models/repo/release.go
index ff31ec4510..223d3f2501 100644
--- a/models/repo/release.go
+++ b/models/repo/release.go
@@ -207,6 +207,21 @@ func GetReleaseByID(ctx context.Context, id int64) (*Release, error) {
 	return rel, nil
 }
 
+// GetReleaseForRepoByID returns release with given ID.
+func GetReleaseForRepoByID(ctx context.Context, repoID, id int64) (*Release, error) {
+	rel := new(Release)
+	has, err := db.GetEngine(ctx).
+		Where("id=? AND repo_id=?", id, repoID).
+		Get(rel)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrReleaseNotExist{id, ""}
+	}
+
+	return rel, nil
+}
+
 // FindReleasesOptions describes the conditions to Find releases
 type FindReleasesOptions struct {
 	db.ListOptions
diff --git a/models/webhook/webhook.go b/models/webhook/webhook.go
index 408023507a..a72bd938aa 100644
--- a/models/webhook/webhook.go
+++ b/models/webhook/webhook.go
@@ -392,39 +392,40 @@ func CreateWebhooks(ctx context.Context, ws []*Webhook) error {
 	return db.Insert(ctx, ws)
 }
 
-// getWebhook uses argument bean as query condition,
-// ID must be specified and do not assign unnecessary fields.
-func getWebhook(ctx context.Context, bean *Webhook) (*Webhook, error) {
-	has, err := db.GetEngine(ctx).Get(bean)
+// GetWebhookByID returns webhook of repository by given ID.
+func GetWebhookByID(ctx context.Context, id int64) (*Webhook, error) {
+	bean := new(Webhook)
+	has, err := db.GetEngine(ctx).ID(id).Get(bean)
 	if err != nil {
 		return nil, err
 	} else if !has {
-		return nil, ErrWebhookNotExist{ID: bean.ID}
+		return nil, ErrWebhookNotExist{ID: id}
 	}
 	return bean, nil
 }
 
-// GetWebhookByID returns webhook of repository by given ID.
-func GetWebhookByID(ctx context.Context, id int64) (*Webhook, error) {
-	return getWebhook(ctx, &Webhook{
-		ID: id,
-	})
-}
-
 // GetWebhookByRepoID returns webhook of repository by given ID.
 func GetWebhookByRepoID(ctx context.Context, repoID, id int64) (*Webhook, error) {
-	return getWebhook(ctx, &Webhook{
-		ID:     id,
-		RepoID: repoID,
-	})
+	webhook := new(Webhook)
+	has, err := db.GetEngine(ctx).Where("id=? AND repo_id=?", id, repoID).Get(webhook)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrWebhookNotExist{ID: id}
+	}
+	return webhook, nil
 }
 
 // GetWebhookByOwnerID returns webhook of a user or organization by given ID.
 func GetWebhookByOwnerID(ctx context.Context, ownerID, id int64) (*Webhook, error) {
-	return getWebhook(ctx, &Webhook{
-		ID:      id,
-		OwnerID: ownerID,
-	})
+	webhook := new(Webhook)
+	has, err := db.GetEngine(ctx).Where("id=? AND owner_id=?", id, ownerID).Get(webhook)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrWebhookNotExist{ID: id}
+	}
+	return webhook, nil
 }
 
 // ListWebhookOptions are options to filter webhooks on ListWebhooksByOpts
@@ -461,20 +462,20 @@ func UpdateWebhookLastStatus(ctx context.Context, w *Webhook) error {
 	return err
 }
 
-// deleteWebhook uses argument bean as query condition,
+// DeleteWebhookByID uses argument bean as query condition,
 // ID must be specified and do not assign unnecessary fields.
-func deleteWebhook(ctx context.Context, bean *Webhook) (err error) {
+func DeleteWebhookByID(ctx context.Context, id int64) (err error) {
 	ctx, committer, err := db.TxContext(ctx)
 	if err != nil {
 		return err
 	}
 	defer committer.Close()
 
-	if count, err := db.DeleteByBean(ctx, bean); err != nil {
+	if count, err := db.DeleteByID(ctx, id, new(Webhook)); err != nil {
 		return err
 	} else if count == 0 {
-		return ErrWebhookNotExist{ID: bean.ID}
-	} else if _, err = db.DeleteByBean(ctx, &HookTask{HookID: bean.ID}); err != nil {
+		return ErrWebhookNotExist{ID: id}
+	} else if _, err = db.DeleteByBean(ctx, &HookTask{HookID: id}); err != nil {
 		return err
 	}
 
@@ -483,16 +484,16 @@ func deleteWebhook(ctx context.Context, bean *Webhook) (err error) {
 
 // DeleteWebhookByRepoID deletes webhook of repository by given ID.
 func DeleteWebhookByRepoID(ctx context.Context, repoID, id int64) error {
-	return deleteWebhook(ctx, &Webhook{
-		ID:     id,
-		RepoID: repoID,
-	})
+	if _, err := GetWebhookByRepoID(ctx, repoID, id); err != nil {
+		return err
+	}
+	return DeleteWebhookByID(ctx, id)
 }
 
 // DeleteWebhookByOwnerID deletes webhook of a user or organization by given ID.
 func DeleteWebhookByOwnerID(ctx context.Context, ownerID, id int64) error {
-	return deleteWebhook(ctx, &Webhook{
-		ID:      id,
-		OwnerID: ownerID,
-	})
+	if _, err := GetWebhookByOwnerID(ctx, ownerID, id); err != nil {
+		return err
+	}
+	return DeleteWebhookByID(ctx, id)
 }
diff --git a/routers/api/v1/api.go b/routers/api/v1/api.go
index 2a41619c3c..623c798fee 100644
--- a/routers/api/v1/api.go
+++ b/routers/api/v1/api.go
@@ -1259,8 +1259,8 @@ func Routes() *web.Route {
 			m.Group("/{username}/{reponame}", func() {
 				m.Group("/issues", func() {
 					m.Combo("").Get(repo.ListIssues).
-						Post(reqToken(), mustNotBeArchived, bind(api.CreateIssueOption{}), repo.CreateIssue)
-					m.Get("/pinned", repo.ListPinnedIssues)
+						Post(reqToken(), mustNotBeArchived, bind(api.CreateIssueOption{}), reqRepoReader(unit.TypeIssues), repo.CreateIssue)
+					m.Get("/pinned", reqRepoReader(unit.TypeIssues), repo.ListPinnedIssues)
 					m.Group("/comments", func() {
 						m.Get("", repo.ListRepoIssueComments)
 						m.Group("/{id}", func() {
diff --git a/routers/api/v1/repo/issue.go b/routers/api/v1/repo/issue.go
index 74e6361f6c..0f76a4b4ff 100644
--- a/routers/api/v1/repo/issue.go
+++ b/routers/api/v1/repo/issue.go
@@ -462,6 +462,24 @@ func ListIssues(ctx *context.APIContext) {
 		isPull = util.OptionalBoolNone
 	}
 
+	if isPull != util.OptionalBoolNone && !ctx.Repo.CanReadIssuesOrPulls(isPull.IsTrue()) {
+		ctx.NotFound()
+		return
+	}
+
+	if isPull == util.OptionalBoolNone {
+		canReadIssues := ctx.Repo.CanRead(unit.TypeIssues)
+		canReadPulls := ctx.Repo.CanRead(unit.TypePullRequests)
+		if !canReadIssues && !canReadPulls {
+			ctx.NotFound()
+			return
+		} else if !canReadIssues {
+			isPull = util.OptionalBoolTrue
+		} else if !canReadPulls {
+			isPull = util.OptionalBoolFalse
+		}
+	}
+
 	// FIXME: we should be more efficient here
 	createdByID := getUserIDForFilter(ctx, "created_by")
 	if ctx.Written() {
@@ -593,6 +611,10 @@ func GetIssue(ctx *context.APIContext) {
 		}
 		return
 	}
+	if !ctx.Repo.CanReadIssuesOrPulls(issue.IsPull) {
+		ctx.NotFound()
+		return
+	}
 	ctx.JSON(http.StatusOK, convert.ToAPIIssue(ctx, issue))
 }
 
diff --git a/routers/api/v1/repo/issue_comment.go b/routers/api/v1/repo/issue_comment.go
index c718424f7e..4db2c68a79 100644
--- a/routers/api/v1/repo/issue_comment.go
+++ b/routers/api/v1/repo/issue_comment.go
@@ -12,9 +12,11 @@ import (
 	issues_model "code.gitea.io/gitea/models/issues"
 	access_model "code.gitea.io/gitea/models/perm/access"
 	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unit"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/context"
 	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/routers/api/v1/utils"
 	"code.gitea.io/gitea/services/convert"
@@ -71,6 +73,11 @@ func ListIssueComments(ctx *context.APIContext) {
 		ctx.Error(http.StatusInternalServerError, "GetRawIssueByIndex", err)
 		return
 	}
+	if !ctx.Repo.CanReadIssuesOrPulls(issue.IsPull) {
+		ctx.NotFound()
+		return
+	}
+
 	issue.Repo = ctx.Repo.Repository
 
 	opts := &issues_model.FindCommentsOptions{
@@ -271,12 +278,27 @@ func ListRepoIssueComments(ctx *context.APIContext) {
 		return
 	}
 
+	var isPull util.OptionalBool
+	canReadIssue := ctx.Repo.CanRead(unit.TypeIssues)
+	canReadPull := ctx.Repo.CanRead(unit.TypePullRequests)
+	if canReadIssue && canReadPull {
+		isPull = util.OptionalBoolNone
+	} else if canReadIssue {
+		isPull = util.OptionalBoolFalse
+	} else if canReadPull {
+		isPull = util.OptionalBoolTrue
+	} else {
+		ctx.NotFound()
+		return
+	}
+
 	opts := &issues_model.FindCommentsOptions{
 		ListOptions: utils.GetListOptions(ctx),
 		RepoID:      ctx.Repo.Repository.ID,
 		Type:        issues_model.CommentTypeComment,
 		Since:       since,
 		Before:      before,
+		IsPull:      isPull,
 	}
 
 	comments, err := issues_model.FindComments(ctx, opts)
@@ -367,6 +389,11 @@ func CreateIssueComment(ctx *context.APIContext) {
 		return
 	}
 
+	if !ctx.Repo.CanReadIssuesOrPulls(issue.IsPull) {
+		ctx.NotFound()
+		return
+	}
+
 	if issue.IsLocked && !ctx.Repo.CanWriteIssuesOrPulls(issue.IsPull) && !ctx.Doer.IsAdmin {
 		ctx.Error(http.StatusForbidden, "CreateIssueComment", errors.New(ctx.Tr("repo.issues.comment_on_locked")))
 		return
@@ -436,6 +463,11 @@ func GetIssueComment(ctx *context.APIContext) {
 		return
 	}
 
+	if !ctx.Repo.CanReadIssuesOrPulls(comment.Issue.IsPull) {
+		ctx.NotFound()
+		return
+	}
+
 	if comment.Type != issues_model.CommentTypeComment {
 		ctx.Status(http.StatusNoContent)
 		return
@@ -555,7 +587,17 @@ func editIssueComment(ctx *context.APIContext, form api.EditIssueCommentOption)
 		return
 	}
 
-	if !ctx.IsSigned || (ctx.Doer.ID != comment.PosterID && !ctx.Repo.IsAdmin()) {
+	if err := comment.LoadIssue(ctx); err != nil {
+		ctx.Error(http.StatusInternalServerError, "LoadIssue", err)
+		return
+	}
+
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.Status(http.StatusNotFound)
+		return
+	}
+
+	if !ctx.IsSigned || (ctx.Doer.ID != comment.PosterID && !ctx.Repo.CanWriteIssuesOrPulls(comment.Issue.IsPull)) {
 		ctx.Status(http.StatusForbidden)
 		return
 	}
@@ -658,7 +700,17 @@ func deleteIssueComment(ctx *context.APIContext) {
 		return
 	}
 
-	if !ctx.IsSigned || (ctx.Doer.ID != comment.PosterID && !ctx.Repo.IsAdmin()) {
+	if err := comment.LoadIssue(ctx); err != nil {
+		ctx.Error(http.StatusInternalServerError, "LoadIssue", err)
+		return
+	}
+
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.Status(http.StatusNotFound)
+		return
+	}
+
+	if !ctx.IsSigned || (ctx.Doer.ID != comment.PosterID && !ctx.Repo.CanWriteIssuesOrPulls(comment.Issue.IsPull)) {
 		ctx.Status(http.StatusForbidden)
 		return
 	} else if comment.Type != issues_model.CommentTypeComment {
diff --git a/routers/api/v1/repo/issue_comment_attachment.go b/routers/api/v1/repo/issue_comment_attachment.go
index c327c54d10..21e2f4dabd 100644
--- a/routers/api/v1/repo/issue_comment_attachment.go
+++ b/routers/api/v1/repo/issue_comment_attachment.go
@@ -329,6 +329,10 @@ func getIssueCommentSafe(ctx *context.APIContext) *issues_model.Comment {
 		return nil
 	}
 
+	if !ctx.Repo.CanReadIssuesOrPulls(comment.Issue.IsPull) {
+		return nil
+	}
+
 	comment.Issue.Repo = ctx.Repo.Repository
 
 	return comment
diff --git a/routers/api/v1/repo/issue_reaction.go b/routers/api/v1/repo/issue_reaction.go
index 29c99184e7..c886bd71b7 100644
--- a/routers/api/v1/repo/issue_reaction.go
+++ b/routers/api/v1/repo/issue_reaction.go
@@ -61,6 +61,12 @@ func GetIssueCommentReactions(ctx *context.APIContext) {
 
 	if err := comment.LoadIssue(ctx); err != nil {
 		ctx.Error(http.StatusInternalServerError, "comment.LoadIssue", err)
+		return
+	}
+
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.NotFound()
+		return
 	}
 
 	if !ctx.Repo.CanReadIssuesOrPulls(comment.Issue.IsPull) {
@@ -190,9 +196,19 @@ func changeIssueCommentReaction(ctx *context.APIContext, form api.EditReactionOp
 		return
 	}
 
-	err = comment.LoadIssue(ctx)
-	if err != nil {
+	if err = comment.LoadIssue(ctx); err != nil {
 		ctx.Error(http.StatusInternalServerError, "comment.LoadIssue() failed", err)
+		return
+	}
+
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.NotFound()
+		return
+	}
+
+	if !ctx.Repo.CanReadIssuesOrPulls(comment.Issue.IsPull) {
+		ctx.NotFound()
+		return
 	}
 
 	if comment.Issue.IsLocked && !ctx.Repo.CanWriteIssuesOrPulls(comment.Issue.IsPull) {
diff --git a/routers/api/v1/repo/key.go b/routers/api/v1/repo/key.go
index 3dc5a60d1c..af48c40885 100644
--- a/routers/api/v1/repo/key.go
+++ b/routers/api/v1/repo/key.go
@@ -153,6 +153,12 @@ func GetDeployKey(ctx *context.APIContext) {
 		return
 	}
 
+	// this check make it more consistent
+	if key.RepoID != ctx.Repo.Repository.ID {
+		ctx.NotFound()
+		return
+	}
+
 	if err = key.GetContent(ctx); err != nil {
 		ctx.Error(http.StatusInternalServerError, "GetContent", err)
 		return
diff --git a/routers/api/v1/repo/release.go b/routers/api/v1/repo/release.go
index 61e5bdd679..6c70bffca3 100644
--- a/routers/api/v1/repo/release.go
+++ b/routers/api/v1/repo/release.go
@@ -49,13 +49,12 @@ func GetRelease(ctx *context.APIContext) {
 	//     "$ref": "#/responses/notFound"
 
 	id := ctx.ParamsInt64(":id")
-	release, err := repo_model.GetReleaseByID(ctx, id)
+	release, err := repo_model.GetReleaseForRepoByID(ctx, ctx.Repo.Repository.ID, id)
 	if err != nil && !repo_model.IsErrReleaseNotExist(err) {
-		ctx.Error(http.StatusInternalServerError, "GetReleaseByID", err)
+		ctx.Error(http.StatusInternalServerError, "GetReleaseForRepoByID", err)
 		return
 	}
-	if err != nil && repo_model.IsErrReleaseNotExist(err) ||
-		release.IsTag || release.RepoID != ctx.Repo.Repository.ID {
+	if err != nil && repo_model.IsErrReleaseNotExist(err) || release.IsTag {
 		ctx.NotFound()
 		return
 	}
@@ -315,13 +314,12 @@ func EditRelease(ctx *context.APIContext) {
 
 	form := web.GetForm(ctx).(*api.EditReleaseOption)
 	id := ctx.ParamsInt64(":id")
-	rel, err := repo_model.GetReleaseByID(ctx, id)
+	rel, err := repo_model.GetReleaseForRepoByID(ctx, ctx.Repo.Repository.ID, id)
 	if err != nil && !repo_model.IsErrReleaseNotExist(err) {
-		ctx.Error(http.StatusInternalServerError, "GetReleaseByID", err)
+		ctx.Error(http.StatusInternalServerError, "GetReleaseForRepoByID", err)
 		return
 	}
-	if err != nil && repo_model.IsErrReleaseNotExist(err) ||
-		rel.IsTag || rel.RepoID != ctx.Repo.Repository.ID {
+	if err != nil && repo_model.IsErrReleaseNotExist(err) || rel.IsTag {
 		ctx.NotFound()
 		return
 	}
@@ -393,17 +391,16 @@ func DeleteRelease(ctx *context.APIContext) {
 	//     "$ref": "#/responses/empty"
 
 	id := ctx.ParamsInt64(":id")
-	rel, err := repo_model.GetReleaseByID(ctx, id)
+	rel, err := repo_model.GetReleaseForRepoByID(ctx, ctx.Repo.Repository.ID, id)
 	if err != nil && !repo_model.IsErrReleaseNotExist(err) {
-		ctx.Error(http.StatusInternalServerError, "GetReleaseByID", err)
+		ctx.Error(http.StatusInternalServerError, "GetReleaseForRepoByID", err)
 		return
 	}
-	if err != nil && repo_model.IsErrReleaseNotExist(err) ||
-		rel.IsTag || rel.RepoID != ctx.Repo.Repository.ID {
+	if err != nil && repo_model.IsErrReleaseNotExist(err) || rel.IsTag {
 		ctx.NotFound()
 		return
 	}
-	if err := release_service.DeleteReleaseByID(ctx, id, ctx.Doer, false); err != nil {
+	if err := release_service.DeleteReleaseByID(ctx, ctx.Repo.Repository, rel, ctx.Doer, false); err != nil {
 		if models.IsErrProtectedTagName(err) {
 			ctx.Error(http.StatusMethodNotAllowed, "delTag", "user not allowed to delete protected tag")
 			return
diff --git a/routers/api/v1/repo/release_attachment.go b/routers/api/v1/repo/release_attachment.go
index 168ef550c5..c36bf12e6d 100644
--- a/routers/api/v1/repo/release_attachment.go
+++ b/routers/api/v1/repo/release_attachment.go
@@ -17,6 +17,23 @@ import (
 	"code.gitea.io/gitea/services/convert"
 )
 
+func checkReleaseMatchRepo(ctx *context.APIContext, releaseID int64) bool {
+	release, err := repo_model.GetReleaseByID(ctx, releaseID)
+	if err != nil {
+		if repo_model.IsErrReleaseNotExist(err) {
+			ctx.NotFound()
+			return false
+		}
+		ctx.Error(http.StatusInternalServerError, "GetReleaseByID", err)
+		return false
+	}
+	if release.RepoID != ctx.Repo.Repository.ID {
+		ctx.NotFound()
+		return false
+	}
+	return true
+}
+
 // GetReleaseAttachment gets a single attachment of the release
 func GetReleaseAttachment(ctx *context.APIContext) {
 	// swagger:operation GET /repos/{owner}/{repo}/releases/{id}/assets/{attachment_id} repository repoGetReleaseAttachment
@@ -54,6 +71,10 @@ func GetReleaseAttachment(ctx *context.APIContext) {
 	//     "$ref": "#/responses/notFound"
 
 	releaseID := ctx.ParamsInt64(":id")
+	if !checkReleaseMatchRepo(ctx, releaseID) {
+		return
+	}
+
 	attachID := ctx.ParamsInt64(":attachment_id")
 	attach, err := repo_model.GetAttachmentByID(ctx, attachID)
 	if err != nil {
@@ -176,13 +197,7 @@ func CreateReleaseAttachment(ctx *context.APIContext) {
 
 	// Check if release exists an load release
 	releaseID := ctx.ParamsInt64(":id")
-	release, err := repo_model.GetReleaseByID(ctx, releaseID)
-	if err != nil {
-		if repo_model.IsErrReleaseNotExist(err) {
-			ctx.NotFound()
-			return
-		}
-		ctx.Error(http.StatusInternalServerError, "GetReleaseByID", err)
+	if !checkReleaseMatchRepo(ctx, releaseID) {
 		return
 	}
 
@@ -203,7 +218,7 @@ func CreateReleaseAttachment(ctx *context.APIContext) {
 	attach, err := attachment.UploadAttachment(ctx, file, setting.Repository.Release.AllowedTypes, header.Size, &repo_model.Attachment{
 		Name:       filename,
 		UploaderID: ctx.Doer.ID,
-		RepoID:     release.RepoID,
+		RepoID:     ctx.Repo.Repository.ID,
 		ReleaseID:  releaseID,
 	})
 	if err != nil {
@@ -264,6 +279,10 @@ func EditReleaseAttachment(ctx *context.APIContext) {
 
 	// Check if release exists an load release
 	releaseID := ctx.ParamsInt64(":id")
+	if !checkReleaseMatchRepo(ctx, releaseID) {
+		return
+	}
+
 	attachID := ctx.ParamsInt64(":attachment_id")
 	attach, err := repo_model.GetAttachmentByID(ctx, attachID)
 	if err != nil {
@@ -328,6 +347,10 @@ func DeleteReleaseAttachment(ctx *context.APIContext) {
 
 	// Check if release exists an load release
 	releaseID := ctx.ParamsInt64(":id")
+	if !checkReleaseMatchRepo(ctx, releaseID) {
+		return
+	}
+
 	attachID := ctx.ParamsInt64(":attachment_id")
 	attach, err := repo_model.GetAttachmentByID(ctx, attachID)
 	if err != nil {
diff --git a/routers/api/v1/repo/release_tags.go b/routers/api/v1/repo/release_tags.go
index 926a713c94..9f2098df06 100644
--- a/routers/api/v1/repo/release_tags.go
+++ b/routers/api/v1/repo/release_tags.go
@@ -112,7 +112,7 @@ func DeleteReleaseByTag(ctx *context.APIContext) {
 		return
 	}
 
-	if err = releaseservice.DeleteReleaseByID(ctx, release.ID, ctx.Doer, false); err != nil {
+	if err = releaseservice.DeleteReleaseByID(ctx, ctx.Repo.Repository, release, ctx.Doer, false); err != nil {
 		if models.IsErrProtectedTagName(err) {
 			ctx.Error(http.StatusMethodNotAllowed, "delTag", "user not allowed to delete protected tag")
 			return
diff --git a/routers/api/v1/repo/tag.go b/routers/api/v1/repo/tag.go
index dbc8df0ef8..2f19f95e66 100644
--- a/routers/api/v1/repo/tag.go
+++ b/routers/api/v1/repo/tag.go
@@ -272,7 +272,7 @@ func DeleteTag(ctx *context.APIContext) {
 		return
 	}
 
-	if err = releaseservice.DeleteReleaseByID(ctx, tag.ID, ctx.Doer, true); err != nil {
+	if err = releaseservice.DeleteReleaseByID(ctx, ctx.Repo.Repository, tag, ctx.Doer, true); err != nil {
 		if models.IsErrProtectedTagName(err) {
 			ctx.Error(http.StatusMethodNotAllowed, "delTag", "user not allowed to delete protected tag")
 			return
diff --git a/routers/api/v1/user/app.go b/routers/api/v1/user/app.go
index edbc1d17b4..f045fb4d5d 100644
--- a/routers/api/v1/user/app.go
+++ b/routers/api/v1/user/app.go
@@ -342,6 +342,10 @@ func GetOauth2Application(ctx *context.APIContext) {
 		}
 		return
 	}
+	if app.UID != ctx.Doer.ID {
+		ctx.NotFound()
+		return
+	}
 
 	app.ClientSecret = ""
 
diff --git a/routers/api/v1/user/gpg_key.go b/routers/api/v1/user/gpg_key.go
index 404b1d221e..4f8bcaca3e 100644
--- a/routers/api/v1/user/gpg_key.go
+++ b/routers/api/v1/user/gpg_key.go
@@ -112,7 +112,7 @@ func GetGPGKey(ctx *context.APIContext) {
 	//   "404":
 	//     "$ref": "#/responses/notFound"
 
-	key, err := asymkey_model.GetGPGKeyByID(ctx, ctx.ParamsInt64(":id"))
+	key, err := asymkey_model.GetGPGKeyForUserByID(ctx, ctx.Doer.ID, ctx.ParamsInt64(":id"))
 	if err != nil {
 		if asymkey_model.IsErrGPGKeyNotExist(err) {
 			ctx.NotFound()
diff --git a/routers/api/v1/user/hook.go b/routers/api/v1/user/hook.go
index 50be519c81..e87385e4a2 100644
--- a/routers/api/v1/user/hook.go
+++ b/routers/api/v1/user/hook.go
@@ -62,6 +62,11 @@ func GetHook(ctx *context.APIContext) {
 		return
 	}
 
+	if !ctx.Doer.IsAdmin && hook.OwnerID != ctx.Doer.ID {
+		ctx.NotFound()
+		return
+	}
+
 	apiHook, err := webhook_service.ToHook(ctx.Doer.HomeLink(), hook)
 	if err != nil {
 		ctx.InternalServerError(err)
diff --git a/routers/web/repo/issue.go b/routers/web/repo/issue.go
index fad4a10de8..3ea40fe8c9 100644
--- a/routers/web/repo/issue.go
+++ b/routers/web/repo/issue.go
@@ -3106,6 +3106,11 @@ func UpdateCommentContent(ctx *context.Context) {
 		return
 	}
 
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.NotFound("CompareRepoID", issues_model.ErrCommentNotExist{})
+		return
+	}
+
 	if !ctx.IsSigned || (ctx.Doer.ID != comment.PosterID && !ctx.Repo.CanWriteIssuesOrPulls(comment.Issue.IsPull)) {
 		ctx.Error(http.StatusForbidden)
 		return
@@ -3172,6 +3177,11 @@ func DeleteComment(ctx *context.Context) {
 		return
 	}
 
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.NotFound("CompareRepoID", issues_model.ErrCommentNotExist{})
+		return
+	}
+
 	if !ctx.IsSigned || (ctx.Doer.ID != comment.PosterID && !ctx.Repo.CanWriteIssuesOrPulls(comment.Issue.IsPull)) {
 		ctx.Error(http.StatusForbidden)
 		return
@@ -3298,6 +3308,11 @@ func ChangeCommentReaction(ctx *context.Context) {
 		return
 	}
 
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.NotFound("CompareRepoID", issues_model.ErrCommentNotExist{})
+		return
+	}
+
 	if !ctx.IsSigned || (ctx.Doer.ID != comment.PosterID && !ctx.Repo.CanReadIssuesOrPulls(comment.Issue.IsPull)) {
 		if log.IsTrace() {
 			if ctx.IsSigned {
@@ -3441,6 +3456,21 @@ func GetCommentAttachments(ctx *context.Context) {
 		return
 	}
 
+	if err := comment.LoadIssue(ctx); err != nil {
+		ctx.NotFoundOrServerError("LoadIssue", issues_model.IsErrIssueNotExist, err)
+		return
+	}
+
+	if comment.Issue.RepoID != ctx.Repo.Repository.ID {
+		ctx.NotFound("CompareRepoID", issues_model.ErrCommentNotExist{})
+		return
+	}
+
+	if !ctx.Repo.Permission.CanReadIssuesOrPulls(comment.Issue.IsPull) {
+		ctx.NotFound("CanReadIssuesOrPulls", issues_model.ErrCommentNotExist{})
+		return
+	}
+
 	if !comment.Type.HasAttachmentSupport() {
 		ctx.ServerError("GetCommentAttachments", fmt.Errorf("comment type %v does not support attachments", comment.Type))
 		return
diff --git a/routers/web/repo/issue_content_history.go b/routers/web/repo/issue_content_history.go
index 5c378fe9d7..473ab260f3 100644
--- a/routers/web/repo/issue_content_history.go
+++ b/routers/web/repo/issue_content_history.go
@@ -122,7 +122,7 @@ func GetContentHistoryDetail(ctx *context.Context) {
 	}
 
 	historyID := ctx.FormInt64("history_id")
-	history, prevHistory, err := issues_model.GetIssueContentHistoryAndPrev(ctx, historyID)
+	history, prevHistory, err := issues_model.GetIssueContentHistoryAndPrev(ctx, issue.ID, historyID)
 	if err != nil {
 		ctx.JSON(http.StatusNotFound, map[string]any{
 			"message": "Can not find the content history",
diff --git a/routers/web/repo/projects.go b/routers/web/repo/projects.go
index 199a065245..5694575b46 100644
--- a/routers/web/repo/projects.go
+++ b/routers/web/repo/projects.go
@@ -468,7 +468,7 @@ func AddBoardToProjectPost(ctx *context.Context) {
 		return
 	}
 
-	project, err := project_model.GetProjectByID(ctx, ctx.ParamsInt64(":id"))
+	project, err := project_model.GetProjectForRepoByID(ctx, ctx.Repo.Repository.ID, ctx.ParamsInt64(":id"))
 	if err != nil {
 		if project_model.IsErrProjectNotExist(err) {
 			ctx.NotFound("", nil)
diff --git a/routers/web/repo/release.go b/routers/web/repo/release.go
index 5cbd6b3d51..761dadd544 100644
--- a/routers/web/repo/release.go
+++ b/routers/web/repo/release.go
@@ -616,7 +616,27 @@ func DeleteTag(ctx *context.Context) {
 }
 
 func deleteReleaseOrTag(ctx *context.Context, isDelTag bool) {
-	if err := releaseservice.DeleteReleaseByID(ctx, ctx.FormInt64("id"), ctx.Doer, isDelTag); err != nil {
+	redirect := func() {
+		if isDelTag {
+			ctx.JSONRedirect(ctx.Repo.RepoLink + "/tags")
+			return
+		}
+
+		ctx.JSONRedirect(ctx.Repo.RepoLink + "/releases")
+	}
+
+	rel, err := repo_model.GetReleaseForRepoByID(ctx, ctx.Repo.Repository.ID, ctx.FormInt64("id"))
+	if err != nil {
+		if repo_model.IsErrReleaseNotExist(err) {
+			ctx.NotFound("GetReleaseForRepoByID", err)
+		} else {
+			ctx.Flash.Error("DeleteReleaseByID: " + err.Error())
+			redirect()
+		}
+		return
+	}
+
+	if err := releaseservice.DeleteReleaseByID(ctx, ctx.Repo.Repository, rel, ctx.Doer, isDelTag); err != nil {
 		if models.IsErrProtectedTagName(err) {
 			ctx.Flash.Error(ctx.Tr("repo.release.tag_name_protected"))
 		} else {
@@ -630,10 +650,5 @@ func deleteReleaseOrTag(ctx *context.Context, isDelTag bool) {
 		}
 	}
 
-	if isDelTag {
-		ctx.JSONRedirect(ctx.Repo.RepoLink + "/tags")
-		return
-	}
-
-	ctx.JSONRedirect(ctx.Repo.RepoLink + "/releases")
+	redirect()
 }
diff --git a/services/release/release.go b/services/release/release.go
index e0035d42fc..3ba2a3f611 100644
--- a/services/release/release.go
+++ b/services/release/release.go
@@ -301,17 +301,7 @@ func UpdateRelease(ctx context.Context, doer *user_model.User, gitRepo *git.Repo
 }
 
 // DeleteReleaseByID deletes a release and corresponding Git tag by given ID.
-func DeleteReleaseByID(ctx context.Context, id int64, doer *user_model.User, delTag bool) error {
-	rel, err := repo_model.GetReleaseByID(ctx, id)
-	if err != nil {
-		return fmt.Errorf("GetReleaseByID: %w", err)
-	}
-
-	repo, err := repo_model.GetRepositoryByID(ctx, rel.RepoID)
-	if err != nil {
-		return fmt.Errorf("GetRepositoryByID: %w", err)
-	}
-
+func DeleteReleaseByID(ctx context.Context, repo *repo_model.Repository, rel *repo_model.Release, doer *user_model.User, delTag bool) error {
 	if delTag {
 		protectedTags, err := git_model.GetProtectedTags(ctx, rel.RepoID)
 		if err != nil {
@@ -344,19 +334,19 @@ func DeleteReleaseByID(ctx context.Context, id int64, doer *user_model.User, del
 			}, repository.NewPushCommits())
 		notify_service.DeleteRef(ctx, doer, repo, refName)
 
-		if err := repo_model.DeleteReleaseByID(ctx, id); err != nil {
+		if err := repo_model.DeleteReleaseByID(ctx, rel.ID); err != nil {
 			return fmt.Errorf("DeleteReleaseByID: %w", err)
 		}
 	} else {
 		rel.IsTag = true
 
-		if err = repo_model.UpdateRelease(ctx, rel); err != nil {
+		if err := repo_model.UpdateRelease(ctx, rel); err != nil {
 			return fmt.Errorf("Update: %w", err)
 		}
 	}
 
 	rel.Repo = repo
-	if err = rel.LoadAttributes(ctx); err != nil {
+	if err := rel.LoadAttributes(ctx); err != nil {
 		return fmt.Errorf("LoadAttributes: %w", err)
 	}
 
diff --git a/tests/integration/api_comment_attachment_test.go b/tests/integration/api_comment_attachment_test.go
index e211376c3c..95a7a81eb4 100644
--- a/tests/integration/api_comment_attachment_test.go
+++ b/tests/integration/api_comment_attachment_test.go
@@ -35,6 +35,14 @@ func TestAPIGetCommentAttachment(t *testing.T) {
 	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: comment.Issue.RepoID})
 	repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
 
+	t.Run("UnrelatedCommentID", func(t *testing.T) {
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 4})
+		repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
+		token := getUserToken(t, repoOwner.Name, auth_model.AccessTokenScopeWriteIssue)
+		req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/issues/comments/%d/assets/%d?token=%s", repoOwner.Name, repo.Name, comment.ID, attachment.ID, token)
+		MakeRequest(t, req, http.StatusNotFound)
+	})
+
 	session := loginUser(t, repoOwner.Name)
 	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeReadIssue)
 	req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/issues/comments/%d/assets/%d?token=%s", repoOwner.Name, repo.Name, comment.ID, attachment.ID, token)
diff --git a/tests/integration/api_comment_test.go b/tests/integration/api_comment_test.go
index 0be4896105..fe272cf926 100644
--- a/tests/integration/api_comment_test.go
+++ b/tests/integration/api_comment_test.go
@@ -177,12 +177,25 @@ func TestAPIEditComment(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 	const newCommentBody = "This is the new comment body"
 
-	comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{},
+	comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: 8},
 		unittest.Cond("type = ?", issues_model.CommentTypeComment))
 	issue := unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: comment.IssueID})
 	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: issue.RepoID})
 	repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
 
+	t.Run("UnrelatedCommentID", func(t *testing.T) {
+		// Using the ID of a comment that does not belong to the repository must fail
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 4})
+		repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
+		token := getUserToken(t, repoOwner.Name, auth_model.AccessTokenScopeWriteIssue)
+		urlStr := fmt.Sprintf("/api/v1/repos/%s/%s/issues/comments/%d?token=%s",
+			repoOwner.Name, repo.Name, comment.ID, token)
+		req := NewRequestWithValues(t, "PATCH", urlStr, map[string]string{
+			"body": newCommentBody,
+		})
+		MakeRequest(t, req, http.StatusNotFound)
+	})
+
 	token := getUserToken(t, repoOwner.Name, auth_model.AccessTokenScopeWriteIssue)
 	urlStr := fmt.Sprintf("/api/v1/repos/%s/%s/issues/comments/%d?token=%s",
 		repoOwner.Name, repo.Name, comment.ID, token)
@@ -201,12 +214,22 @@ func TestAPIEditComment(t *testing.T) {
 func TestAPIDeleteComment(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
-	comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{},
+	comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: 8},
 		unittest.Cond("type = ?", issues_model.CommentTypeComment))
 	issue := unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: comment.IssueID})
 	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: issue.RepoID})
 	repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
 
+	t.Run("UnrelatedCommentID", func(t *testing.T) {
+		// Using the ID of a comment that does not belong to the repository must fail
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 4})
+		repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
+		token := getUserToken(t, repoOwner.Name, auth_model.AccessTokenScopeWriteIssue)
+		req := NewRequestf(t, "DELETE", "/api/v1/repos/%s/%s/issues/comments/%d?token=%s",
+			repoOwner.Name, repo.Name, comment.ID, token)
+		MakeRequest(t, req, http.StatusNotFound)
+	})
+
 	token := getUserToken(t, repoOwner.Name, auth_model.AccessTokenScopeWriteIssue)
 	req := NewRequestf(t, "DELETE", "/api/v1/repos/%s/%s/issues/comments/%d?token=%s",
 		repoOwner.Name, repo.Name, comment.ID, token)
diff --git a/tests/integration/api_issue_reaction_test.go b/tests/integration/api_issue_reaction_test.go
index 7d3ee2d154..124d729353 100644
--- a/tests/integration/api_issue_reaction_test.go
+++ b/tests/integration/api_issue_reaction_test.go
@@ -12,6 +12,7 @@ import (
 	auth_model "code.gitea.io/gitea/models/auth"
 	"code.gitea.io/gitea/models/db"
 	issues_model "code.gitea.io/gitea/models/issues"
+	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
 	api "code.gitea.io/gitea/modules/structs"
@@ -107,6 +108,26 @@ func TestAPICommentReactions(t *testing.T) {
 	})
 	MakeRequest(t, req, http.StatusOK)
 
+	t.Run("UnrelatedCommentID", func(t *testing.T) {
+		// Using the ID of a comment that does not belong to the repository must fail
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 4})
+		repoOwner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
+		token := getUserToken(t, repoOwner.Name, auth_model.AccessTokenScopeWriteIssue)
+		urlStr := fmt.Sprintf("/api/v1/repos/%s/%s/issues/comments/%d/reactions?token=%s",
+			repoOwner.Name, repo.Name, comment.ID, token)
+		req = NewRequestWithJSON(t, "POST", urlStr, &api.EditReactionOption{
+			Reaction: "+1",
+		})
+		MakeRequest(t, req, http.StatusNotFound)
+		req = NewRequestWithJSON(t, "DELETE", urlStr, &api.EditReactionOption{
+			Reaction: "+1",
+		})
+		MakeRequest(t, req, http.StatusNotFound)
+
+		req = NewRequestf(t, "GET", urlStr)
+		MakeRequest(t, req, http.StatusNotFound)
+	})
+
 	// Add allowed reaction
 	req = NewRequestWithJSON(t, "POST", urlStr, &api.EditReactionOption{
 		Reaction: "+1",
diff --git a/tests/integration/api_keys_test.go b/tests/integration/api_keys_test.go
index 238c3cb823..03d28c9126 100644
--- a/tests/integration/api_keys_test.go
+++ b/tests/integration/api_keys_test.go
@@ -72,6 +72,17 @@ func TestCreateReadOnlyDeployKey(t *testing.T) {
 		Content: rawKeyBody.Key,
 		Mode:    perm.AccessModeRead,
 	})
+
+	// Using the ID of a key that does not belong to the repository must fail
+	{
+		req := NewRequest(t, "GET", fmt.Sprintf("/api/v1/repos/%s/%s/keys/%d?token=%s", repoOwner.Name, repo.Name, newDeployKey.ID, token))
+		MakeRequest(t, req, http.StatusOK)
+
+		session5 := loginUser(t, "user5")
+		token5 := getTokenForLoggedInUser(t, session5, auth_model.AccessTokenScopeWriteRepository)
+		req = NewRequest(t, "GET", fmt.Sprintf("/api/v1/repos/user5/repo4/keys/%d?token=%s", newDeployKey.ID, token5))
+		MakeRequest(t, req, http.StatusNotFound)
+	}
 }
 
 func TestCreateReadWriteDeployKey(t *testing.T) {
diff --git a/tests/integration/api_nodeinfo_test.go b/tests/integration/api_nodeinfo_test.go
index 4cbd25f5de..fb35d72ac2 100644
--- a/tests/integration/api_nodeinfo_test.go
+++ b/tests/integration/api_nodeinfo_test.go
@@ -34,6 +34,6 @@ func TestNodeinfo(t *testing.T) {
 		assert.Equal(t, "gitea", nodeinfo.Software.Name)
 		assert.Equal(t, 25, nodeinfo.Usage.Users.Total)
 		assert.Equal(t, 20, nodeinfo.Usage.LocalPosts)
-		assert.Equal(t, 2, nodeinfo.Usage.LocalComments)
+		assert.Equal(t, 3, nodeinfo.Usage.LocalComments)
 	})
 }
diff --git a/tests/integration/issue_test.go b/tests/integration/issue_test.go
index ac06b487db..b1080c998a 100644
--- a/tests/integration/issue_test.go
+++ b/tests/integration/issue_test.go
@@ -206,6 +206,56 @@ func TestIssueCommentClose(t *testing.T) {
 	assert.Equal(t, "Description", val)
 }
 
+func TestIssueCommentDelete(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+	session := loginUser(t, "user2")
+	issueURL := testNewIssue(t, session, "user2", "repo1", "Title", "Description")
+	comment1 := "Test comment 1"
+	commentID := testIssueAddComment(t, session, issueURL, comment1, "")
+	comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: commentID})
+	assert.Equal(t, comment1, comment.Content)
+
+	// Using the ID of a comment that does not belong to the repository must fail
+	req := NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/%s/comments/%d/delete", "user5", "repo4", commentID), map[string]string{
+		"_csrf": GetCSRF(t, session, issueURL),
+	})
+	session.MakeRequest(t, req, http.StatusNotFound)
+	req = NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/%s/comments/%d/delete", "user2", "repo1", commentID), map[string]string{
+		"_csrf": GetCSRF(t, session, issueURL),
+	})
+	session.MakeRequest(t, req, http.StatusOK)
+	unittest.AssertNotExistsBean(t, &issues_model.Comment{ID: commentID})
+}
+
+func TestIssueCommentUpdate(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+	session := loginUser(t, "user2")
+	issueURL := testNewIssue(t, session, "user2", "repo1", "Title", "Description")
+	comment1 := "Test comment 1"
+	commentID := testIssueAddComment(t, session, issueURL, comment1, "")
+
+	comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: commentID})
+	assert.Equal(t, comment1, comment.Content)
+
+	modifiedContent := comment.Content + "MODIFIED"
+
+	// Using the ID of a comment that does not belong to the repository must fail
+	req := NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/%s/comments/%d", "user5", "repo4", commentID), map[string]string{
+		"_csrf":   GetCSRF(t, session, issueURL),
+		"content": modifiedContent,
+	})
+	session.MakeRequest(t, req, http.StatusNotFound)
+
+	req = NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/%s/comments/%d", "user2", "repo1", commentID), map[string]string{
+		"_csrf":   GetCSRF(t, session, issueURL),
+		"content": modifiedContent,
+	})
+	session.MakeRequest(t, req, http.StatusOK)
+
+	comment = unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: commentID})
+	assert.Equal(t, modifiedContent, comment.Content)
+}
+
 func TestIssueReaction(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 	session := loginUser(t, "user2")
diff --git a/tests/integration/mirror_pull_test.go b/tests/integration/mirror_pull_test.go
index e1c7c6b170..c02e16bfc0 100644
--- a/tests/integration/mirror_pull_test.go
+++ b/tests/integration/mirror_pull_test.go
@@ -88,7 +88,7 @@ func TestMirrorPull(t *testing.T) {
 
 	release, err := repo_model.GetRelease(db.DefaultContext, repo.ID, "v0.2")
 	assert.NoError(t, err)
-	assert.NoError(t, release_service.DeleteReleaseByID(ctx, release.ID, user, true))
+	assert.NoError(t, release_service.DeleteReleaseByID(ctx, repo, release, user, true))
 
 	ok = mirror_service.SyncPullMirror(ctx, mirror.ID)
 	assert.True(t, ok)