CVE-2026-109167

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

5.3 Medium

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: Low
Availability: None

Exploit likelihood

0.19%Unchanged since Oct 13, 2026

What each source reports

CVE List Score used 5.3

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

Record: CVE-2026-109167
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-639
Updated: 2026-11-02

EUVDEUVD-2026-97373 5.3

Record: EUVD-2026-97373
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-w8cw-4mm2-mrw7 5.3

TDuck survey form through 6.0 contains an insecure direct object reference vulnerability in the...

Record: GHSA-w8cw-4mm2-mrw7
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-639
Updated: 2026-11-02

NVD 5.3

Record: CVE-2026-109167
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-639
Updated: 2026-11-02

Affected products

tduckcloud tduck-survey-form

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-109167 is a medium vulnerability (CVSS 5.3) in Tduckcloud Tduck-survey-form, published October 12, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.19%, the 8th percentile. No source names a fixed version.