CVE-2026-8823GO-2026-6547GHSA-XMFH-3CCG-C9FX
User Manager can demote bot accounts to guest without bot-management permission
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 10.11.18+incompatible, 11.7.1+incompatible, 8.0.0-20260518160100-9bd77d3fc4d2, 11.7.1, 10.11.18
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Mattermost Mattermost
From 11.7.0 · through 11.7.0; From 10.11.0 · through 10.11.17
- github.com/mattermost/mattermost-serverGo
From 10.11.0+incompatible · fixed in 10.11.18+incompatible; From 11.7.0+incompatible · fixed in 11.7.1+incompatible
- github.com/mattermost/mattermost-server/v5Go
All versions
- github.com/mattermost/mattermost-server/v6Go
All versions
- github.com/mattermost/mattermost/server/v8Go
fixed in 8.0.0-20260518160100-9bd77d3fc4d2
- github.com/mattermost/mattermost-serverGo
From 11.7.0 · fixed in 11.7.1
- github.com/mattermost/mattermost-serverGo
From 10.11.0 · fixed in 10.11.18