Vulnerability · Published Mar 16, 2026 · Assigned by Mattermost
CVE-2026-26230Team Admin Privilege Escalation to Demote Members to Guest
Low 3.8
In plain English
A low-severity incorrect authorization in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities).
Severity (CVSS 3.1)3.8Low
Exploit odds (30 days)0.2%top 93.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Mattermost versions 10.11.x <= 10.11.10 fail to properly validate permission requirements in the team member roles API endpoint which allows team administrators to demote members to guest role. Mattermost Advisory ID: MMSA-2025-00531
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 10.11.0 – through 10.11.10 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
References
- MMSA-2025-00531 vendor-advisory