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 strip action integration secrets from post payloads before broadcasting post-deletion web socket events and returning thread API responses, which allows an authenticated channel member to obtain server-side webhook URLs and authentication context from interactive-message posts via the post_deleted websocket event or the threads REST API.. Mattermost Advisory ID: MMSA-2026-00766
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Mattermost Mattermost
Default version status: unaffected
11.10.0 to ≤ 11.10.0affected11.7.0 to ≤ 11.7.9affected11.9.0 to ≤ 11.9.1affected11.8.0 to ≤ 11.8.5affected11.11.0unaffected11.10.1unaffected11.7.10unaffected11.9.2unaffected11.8.6unaffected