BaselineWatch
Desk

CVE-2026-5163

6.5 medium SSVC exploitation: none Analyzed

Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to read the content of threads in private channels and direct messages they do not have access to via a crafted request to the post rewrite endpoint.. Mattermost Advisory ID: MMSA-2026-00645

Fix

Patch, vendor advisory and mitigation references on NVD 1

Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.

Change history 1

  1. First seenCVSS 6.5 · mattermostNVD modified 2026-10-14 20:10

Affected (CPE criteria) 1

  • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

References 1