diff --git a/backend/src/middleware/auth/checks/submission-checks.ts b/backend/src/middleware/auth/checks/submission-checks.ts
index 7cd75c8d..46d901e0 100644
--- a/backend/src/middleware/auth/checks/submission-checks.ts
+++ b/backend/src/middleware/auth/checks/submission-checks.ts
@@ -10,9 +10,14 @@ import { AccountType } from '@dwengo-1/common/util/account-types';
 import { fetchClass } from '../../../services/classes.js';
 import { fetchGroup } from '../../../services/groups.js';
 import { requireFields } from '../../../controllers/error-helper.js';
+import { SubmissionDTO } from '@dwengo-1/common/interfaces/submission';
 
 export const onlyAllowSubmitter = authorize(
-    (auth: AuthenticationInfo, req: AuthenticatedRequest) => (req.body as { submitter: string }).submitter === auth.username
+    (auth: AuthenticationInfo, req: AuthenticatedRequest) => {
+        const submittedFor = (req.body as SubmissionDTO).submitter.username;
+        const submittedBy = auth.username;
+        return submittedFor === submittedBy;
+    }
 );
 
 export const onlyAllowIfHasAccessToSubmission = authorize(async (auth: AuthenticationInfo, req: AuthenticatedRequest) => {