CVE-2026-109167

MEDIUM 4.3

TDuck survey form through 6.0 Authorization Bypass via User-Controlled Theme ID in POST /user/form/theme/save

CVSS Score

4.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-639
Vendor	tduckcloud
Product	tduck-survey-form
Published	Oct 12, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Affected Versions

TDuckCloud / tduck-survey-form

0 ≤ 6.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/AnkesKasty/cve-request-poc/blob/a7b6d1423555812d8efa26c91c5d0683164b31e5/tduck/poc_user_form_theme_save_id_confusion.py github.com: https://github.com/TDuckCloud/tduck-survey-form/blob/43ffa9c993e38936fc4de7d8e5aee82bbaa19502/tduck-api/src/main/java/com/tduck/cloud/api/web/controller/UserFormController.java#L393-L405 vulncheck.com: https://www.vulncheck.com/advisories/tduck-survey-form-through-6.0-authorization-bypass-via-user-controlled-theme-id-in-post-user-form-theme-save

Credits

Yaqi Chao