GHSA-57cc-2pf4-mhmx
Mattermost fails to properly validate team membership when processing channel mentions
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/mattermost/mattermost/server/v8 | < 8.0.0-20251209134645-761e56bb11cc | 8.0.0-20251209134645-761e56bb11cc |
| Go | github.com/mattermost/mattermost-server | < 11.1.3 | no fix listed |
| Go | github.com/mattermost/mattermost-server | < 10.11.10 | no fix listed |
| Go | github.com/mattermost/mattermost-server | < 11.2.2 | no fix listed |
| Go | github.com/mattermost/mattermost-server | < 5.3.2-0.20251209134645-761e56bb11cc | 5.3.2-0.20251209134645-761e56bb11cc |
Details
As written in the advisory (Markdown source, shown as plain text).
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate team membership when processing channel mentions which allows authenticated users to determine the existence of teams and their URL names via posting channel shortlinks and observing the channel_mentions property in the API response. Mattermost Advisory ID: MMSA-2025-00563
References
External links from the advisory. They lead to third-party sites.