CVE-2026-3117: Instance and webhook GitLab plugin commands were able to be run by non-admin users

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-18 · updated 2026-10-14
Weakness: CWE-862

Description

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

Affected products

Mattermost: from 10.13.0 through 10.13.11; from 11.1.0 through 11.1.5; from 11.3.0 through 11.3.4

References

https://mattermost.com/security-updates

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