Medium severity6.5NVD Advisory· Published Oct 16, 2026
CVE-2026-18551
CVE-2026-18551
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 validate the combination of guest and admin scheme roles which allows an authenticated attacker to escalate a guest account to team or channel admin via a crafted PUT request to the member roles API endpoint.. Mattermost Advisory ID: MMSA-2026-00752
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
1- Range: <=11.10.0, <=11.7.9, <=11.9.1, <=11.8.5
Patches
Vulnerability mechanics
References
1News mentions
0No linked articles in our index yet.