diff --git a/routers/web/repo/issue.go b/routers/web/repo/issue.go
index a0642165f7..d61c913f2f 100644
--- a/routers/web/repo/issue.go
+++ b/routers/web/repo/issue.go
@@ -3300,6 +3300,11 @@ 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 {