CVE-2026-3117

Instance and webhook GitLab plugin commands were able to be run by non-admin users

6.5 Medium

Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to properly check for permissions when processing commands in the Gitlab plugin which allows normal users to uninstall instances or setup webhook connections via the {{gitlab instance {option}}} or the {{/gitlab webhook {option}}} commands. Mattermost Advisory ID: MMSA-2026-00600

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: None
Availability: High

Exploit likelihood

0.23%Up 0.2 points since May 19, 2026

What each source reports

CVE List Score used 6.5

Instance and webhook GitLab plugin commands were able to be run by non-admin users

Record: CVE-2026-3117
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-862
Updated: 2026-11-02

EUVDEUVD-2026-30748 6.5

Record: EUVD-2026-30748
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-5gjv-5xhr-vc35 6.5

Mattermost Plugins versions <=11.5 11.1.5 10.13.11 11.3.4.0 fail to properly check for...

Record: GHSA-5gjv-5xhr-vc35
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-862
Updated: 2026-11-02

NVD 6.5

Record: CVE-2026-3117
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-862
Updated: 2026-11-02

Affected products

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-2026-3117 is a medium vulnerability (CVSS 6.5) in Mattermost, published May 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.23%, the 13th percentile. No source names a fixed version.