TDuck Survey Form through 5.3 contains a missing authorization vulnerability that allows any authenticated user to read other owners' raw form settings via GET /user/form/setting/{key}. Attackers can supply the 8-character form key from a public fill link to obtain the form write password, owner notification e-mail, and WeChat openIds.

TDuck survey form through 6.0 contains an insecure direct object reference vulnerability in the saveFormTheme handler that allows authenticated users to overwrite other users' form themes. Attackers whose form has no theme can submit another form's sequential theme id with their own formKey, replacing its colours and image URLs and removing the victim's theme.

TDuck survey form through 6.0 contains an insecure direct object reference vulnerability that allows authenticated users to delete other users' form submissions by supplying arbitrary submission ids. Attackers can place their own formKey in the path and iterate sequential submission ids in the request body to permanently delete submissions platform-wide.

TDuck survey form through 6.0 contains a broken access control vulnerability that allows authenticated users to add fields to other users' forms via POST /user/form/item/batch/create. Attackers can submit an array whose first element references their own form and later elements reference a victim's formKey, injecting attacker-chosen fields onto the victim's public fill page.

TDuck survey form through 6.0 fails to validate write passwords on submission endpoints, enforcing the check only on the front end. Remote unauthenticated attackers can submit form entries directly to public submission APIs without providing the password by using the form key from share links.

TDuck survey form through 6.0 fails to enforce form fill-in restrictions on the authenticated submission endpoint POST /user/form/data/create. Authenticated attackers who know a form's key can submit unlimited entries to any form, bypassing publish status, time window, quota, and per-IP restrictions to falsify collected results.

TDuck survey form 6.0 contains an information disclosure vulnerability in FormAuthUtils.hasPermission that fails open when a form does not exist, allowing authenticated users to access deleted form submissions. Attackers can read orphaned submission data including personal information by providing a known dataId to the GET /user/form/data/details endpoint after the form has been permanently deleted.

TDuck survey form through 6.0 lacks authorization checks on FormThemeController write endpoints for global form themes and categories. Authenticated non-admin users can add, modify, or delete themes and theme categories affecting forms owned by other users.