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
Exploitability
AV:NAC:LPR:LUI:NScope
S:UImpact
C:NI:LA:L5.4/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:LAccess Control