diff --git a/routers/web/repo/issue.go b/routers/web/repo/issue.go
index 4e7d558deb..a0642165f7 100644
--- a/routers/web/repo/issue.go
+++ b/routers/web/repo/issue.go
@@ -3098,6 +3098,11 @@ 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