TDuck survey form 6.0 Information Disclosure via Fail-Open Form Ownership Check

Advisories

TDuck survey form 6.0 Information Disclosure via Fail-Open Form Ownership Check

severity: medium
date: 9/25/2026
Affecting: tduck-survey-form 6.0
CVE: CVE-2026-100304
CWE: CWE-636 Not Failing Securely ('Failing Open')
CVSS: 6.0
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
References: https://github.com/LinYuanyi1/cve-request-poc/blob/adffc39b78cad18cd489cbf7454853bf0f744b7f/tduck/poc_form_data_details_orphan.py
https://github.com/TDuckCloud/tduck-survey-form
https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-form/src/main/java/com/tduck/cloud/form/util/FormAuthUtils.java#L25-L39
https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-form/src/main/java/com/tduck/cloud/form/service/impl/UserFormDataServiceImpl.java#L169-L187
https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-api/src/main/java/com/tduck/cloud/api/web/controller/UserFormController.java#L451-L459
Credit: Yaqi Chao, Mingsheng Lin
Description: 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.

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