CVE-2026-26230

Team Admin Privilege Escalation to Demote Members to Guest

CVSS 3.8 LOWEPSS 0.2%CWE-863

Vexday Risk Score

8Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 3.8EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch referenciado

Lifecycle

16 Mar 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

Affected products

Mattermost · Mattermost

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References

https://mattermost.com/security-updates