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OpenAdvisories
Medium · 6.5 CVE-2026-10106 EUVD-2026-43312GHSA-vvv9-9jm4-76jg

Unauthorized users can trigger interactive post actions in private channels via action cookie channel mismatch in Mattermost

Published Jul 13, 2026 · Updated Jul 13, 2026 · Assigned by Mattermost

Description

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify that the channel referenced in an action cookie matches the channel of the target post, which allows an authenticated user without access to a private channel to trigger interactive post actions on posts in that channel via a cookie obtained from any accessible channel.. Mattermost Advisory ID: MMSA-2026-00690

Affected products

VendorProductAffectedFixed
Mattermost Mattermost 11.7.0 – ≤ 11.7.2, 11.6.0 – ≤ 11.6.4, 10.11.0 – ≤ 10.11.19 11.8.0

Advisories 1

References