Mattermost versions 10.11.x <= 10.11.5, 11.0.x <= 11.0.4, 10.12.x <= 10.12.2 fail to invalidate remote cluster invite tokens when using the legacy (version 1) protocol or when the confirming party does not provide a refreshed token, which allows an attacker who has obtained an invite token to authenticate as the remote cluster and perform limited actions on shared channels even after the invitation has been legitimately confirmed.
Fix
Patch, vendor advisory and mitigation references on NVD 1
- https://mattermost.com/security-updates Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 3.7 · mattermostNVD modified 2026-10-13 11:10
Affected (CPE criteria) 1
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
References 1
- https://mattermost.com/security-updates Vendor Advisory