CVE-2026-5139

medium

Description

Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to overwrite the global default GitLab instance configuration via the {{/gitlab connect <instance-name>}} slash command.. Mattermost Advisory ID: MMSA-2026-00644

References

https://mattermost.com/security-updates

Details

Source: Mitre, NVD

Published: 2026-06-22

Updated: 2026-06-23

Risk Information

CVSS v2

Base Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:P/A:P

Severity: Medium

CVSS v3

Base Score: 5.4

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