diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index b1317462c..39f621a66 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "3.1.38",
+    "version": "3.1.39",
     "bin": "bin/hydrooj.js",
     "main": "src/loader",
     "module": "src/loader",
diff --git a/packages/hydrooj/src/handler/problem.ts b/packages/hydrooj/src/handler/problem.ts
index 69bc69c58..5aeb177d2 100644
--- a/packages/hydrooj/src/handler/problem.ts
+++ b/packages/hydrooj/src/handler/problem.ts
@@ -380,8 +380,12 @@ export class ProblemDetailHandler extends ProblemHandler {
 }
 
 export class ProblemSubmitHandler extends ProblemDetailHandler {
-    async get(domainId: string, tid?: ObjectID) {
+    @param('tid', Types.ObjectID, true)
+    async prepare(domainId: string, tid?: ObjectID) {
         if (tid && !contest.isOngoing(this.tdoc)) throw new ContestNotLiveError(this.tdoc.docId);
+    }
+
+    async get() {
         this.response.template = 'problem_submit.html';
         this.response.body = {
             pdoc: this.pdoc,