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OpenAdvisories
Medium · 6.4 CVE-2026-18795 EUVD-2026-102813GHSA-c5qm-9j4f-82mg

Missing server side validation allowed user to quarantine a DM and GM post

Published Oct 16, 2026 · Updated Oct 16, 2026 · Assigned by Mattermost

Description

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

Affected products

VendorProductAffectedFixed
Mattermost Mattermost 11.10.0 – ≤ 11.10.0, 11.7.0 – ≤ 11.7.9, 11.9.0 – ≤ 11.9.1, 11.8.0 – ≤ 11.8.5 11.11.0

Advisories 1

References