TDuck survey form through 6.0 Write Password Bypass via Client-Side Enforcement

Advisories

TDuck survey form through 6.0 Write Password Bypass via Client-Side Enforcement

severity: medium
date: 9/25/2026
Affecting: tduck-survey-form <= 6.0
CVE: CVE-2026-100306
CWE: CWE-602 Client-Side Enforcement of Server-Side Security
CVSS: 6.9
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
References: https://github.com/LinYuanyi1/cve-request-poc/blob/adffc39b78cad18cd489cbf7454853bf0f744b7f/tduck/poc_form_data_create_bypass.py
https://github.com/TDuckCloud/tduck-survey-form
https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-api/src/main/java/com/tduck/cloud/api/web/controller/UserFormSettingController.java#L154-L162
https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-api/src/main/java/com/tduck/cloud/api/web/controller/UserFormResultController.java#L152-L172
Credit: Yaqi Chao, Mingsheng Lin
Description: 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.

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