What is CVE-2026-3117?

CVE-2026-3117 is a medium-severity vulnerability in Mattermost, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-05-18.

How severe is CVE-2026-3117?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Auth bypass in Mattermost

CVE-2026-3117

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…

Vulnerability class: Broken Access Control

EPSS: 0.000 (10.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Mattermost — versions 0, 11.6.0, 11.5.2
Mattermost Mattermost_server

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

responsibledisclosure@mattermost.com (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-3117?: CVE-2026-3117 is a medium-severity vulnerability in Mattermost, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-05-18.
How severe is CVE-2026-3117?: Medium severity. CVSS v3 base score is 6.5 out of 10.