Low severity3.8NVD Advisory· Published Jun 22, 2026· Updated Jun 26, 2026
CVE-2026-8823
CVE-2026-8823
Description
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
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/mattermost/mattermost-serverGo | >= 11.7.0, < 11.7.1 | 11.7.1 |
github.com/mattermost/mattermost-serverGo | >= 10.11.0, < 10.11.18 | 10.11.18 |
github.com/mattermost/mattermost/server/v8Go | < 8.0.0-20260518160100-9bd77d3fc4d2 | 8.0.0-20260518160100-9bd77d3fc4d2 |
Affected products
2cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*range: >=10.11.0,<10.11.18
- (no CPE)range: <=11.7.0, <=10.11.17
Patches
Vulnerability mechanics
References
11- github.com/advisories/GHSA-xmfh-3ccg-c9fxghsaADVISORY
- mattermost.com/security-updatesnvdVendor Advisory
- nvd.nist.gov/vuln/detail/CVE-2026-8823ghsaADVISORY
- docs.mattermost.com/security-guide/security-updatesghsaWEB
- github.com/mattermost/mattermost/commit/7972fc53f5c0b0175879a9737308a87b42db1f0bghsaWEB
- github.com/mattermost/mattermost/commit/9bd77d3fc4d2af3f7f0259a205174e76a1a276e1ghsaWEB
- github.com/mattermost/mattermost/commit/c9bf3609fb9a3e5c2de94c50742c9b91fd723e3dghsaWEB
- github.com/mattermost/mattermost/commit/d9a55e394cd5bc15edb49e9606bec8fec03ac4c6ghsaWEB
- github.com/mattermost/mattermost/pull/36487ghsaWEB
- github.com/mattermost/mattermost/releases/tag/v10.11.18ghsaWEB
- github.com/mattermost/mattermost/releases/tag/v11.7.1ghsaWEB
News mentions
1- Mattermost: Six Vulnerabilities in User Management, Plugins, and Sessions Disclosed TogetherVypr Intelligence · Jun 22, 2026