CVE-2024-39274: Mattermost failed to properly validate that the channel that comes from the sync message is a shared channel
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to properly validate that the channel that comes from the sync message is a shared channel, when shared channels are enabled, which allows a malicious remote to add users to arbitrary teams and channels
Published Aug 1, 2024 · Updated Nov 18, 2024
Affected packages
github.com/mattermost/mattermost/server/v8
- Ecosystem
- Go
- Affected
- >= 9.5.0, < 9.5.7
- Fixed in
- 9.5.7
- Check
go list -m github.com/mattermost/mattermost/server/v8
github.com/mattermost/mattermost/server/v8
- Ecosystem
- Go
- Affected
- >= 9.7.0, < 9.7.6
- Fixed in
- 9.7.6
- Check
go list -m github.com/mattermost/mattermost/server/v8
github.com/mattermost/mattermost/server/v8
- Ecosystem
- Go
- Affected
- >= 9.8.0, < 9.8.2
- Fixed in
- 9.8.2
- Check
go list -m github.com/mattermost/mattermost/server/v8
github.com/mattermost/mattermost/server/v8
- Ecosystem
- Go
- Affected
- = 9.9.0
- Fixed in
- 9.9.1
- Check
go list -m github.com/mattermost/mattermost/server/v8
Advisory details
From the GitHub Advisory Database (CC BY 4.0).
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to properly validate that the channel that comes from the sync message is a shared channel, when shared channels are enabled, which allows a malicious remote to add users to arbitrary teams and channels
References
How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology
More Go vulnerabilities
All Go entriesCVE-2025-12419
Mattermost fails to properly validate OAuth state tokens during OpenID Connect authentication
critical9.9Nov 27, 2025CVE-2025-12421
Mattermost fails to to verify the token used during code exchange
critical9.9Nov 27, 2025CVE-2025-4981
Mattermost allows authenticated users to write files to arbitrary locations
critical9.9Jun 20, 2025CVE-2025-20051
Mattermost allows reading arbitrary files
critical9.9Feb 24, 2025CVE-2025-25279
Mattermost allows reading arbitrary files related to importing boards
critical9.9Feb 24, 2025CVE-2024-39777
Mattermost allows unsolicited invites to expose access to local channels
critical8.7Aug 1, 2024
