GHSA-xmfh-3ccg-c9fx
Mattermost has an Incorrect Authorization issue
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | >= 11.7.0, < 11.7.1 | 11.7.1 |
| Go | github.com/mattermost/mattermost-server | >= 10.11.0, < 10.11.18 | 10.11.18 |
| Go | github.com/mattermost/mattermost/server/v8 | < 8.0.0-20260518160100-9bd77d3fc4d2 | 8.0.0-20260518160100-9bd77d3fc4d2 |
Details
As written in the advisory (Markdown source, shown as plain text).
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
References
External links from the advisory. They lead to third-party sites.
- https://nvd.nist.gov/vuln/detail/CVE-2026-8823
- https://github.com/mattermost/mattermost/pull/36487
- https://github.com/mattermost/mattermost/commit/7972fc53f5c0b0175879a9737308a87b42db1f0b
- https://github.com/mattermost/mattermost/commit/9bd77d3fc4d2af3f7f0259a205174e76a1a276e1
- https://github.com/mattermost/mattermost/commit/c9bf3609fb9a3e5c2de94c50742c9b91fd723e3d
- https://github.com/mattermost/mattermost/commit/d9a55e394cd5bc15edb49e9606bec8fec03ac4c6
- https://docs.mattermost.com/security-guide/security-updates
- https://github.com/mattermost/mattermost
- https://github.com/mattermost/mattermost/releases/tag/v10.11.18
- https://github.com/mattermost/mattermost/releases/tag/v11.7.1