CVE-2026-8823

User Manager can demote bot accounts to guest without bot-management permission

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

22 Jun 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669

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

Affected products

Mattermost · Mattermost

Want to know if your infrastructure is exposed to this?

Talk to TrueHacking →

References

https://mattermost.com/security-updates