Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to enforce DM/GM check on server side which allows an authenticated user to quarantine a post belonging to DM or GM via direct API call.. Mattermost Advisory ID: MMSA-2026-00756
CVE-2026-18795
CVSS base score
6.4 (v3.1)
Severity
MEDIUM
Attack vector
Network
Weakness
CWE-862
Last modified
October 29, 2026
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L
Affected products
mattermost mattermost server
References
- mattermost.com Vendor Advisory