HIGH 8.8
GHSA-6hxm-w4hv-vgvw
Mattermost doesn't require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints
Quick fix
GHSA-6hxm-w4hv-vgvw — github.com/mattermost/mattermost-server: upgrade to the fixed version with the command below.
go get github.com/mattermost/mattermost-server@v11.6.1Details
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to escalate themselves and group members to team or channel admin via crafted API requests. Mattermost Advisory ID: MMSA-2026-00665
Are you affected?
Enter the version of the package you're using.
Affected packages
Go / github.com/mattermost/mattermost-server
Introduced in:
11.6.0 Fixed in: 11.6.1 Fix
go get github.com/mattermost/mattermost-server@v11.6.1 Go / github.com/mattermost/mattermost-server
Introduced in:
11.5.0 Fixed in: 11.5.5 Fix
go get github.com/mattermost/mattermost-server@v11.5.5 Go / github.com/mattermost/mattermost-server
Introduced in:
10.11.0 Fixed in: 10.11.17 Fix
go get github.com/mattermost/mattermost-server@v10.11.17 Go / github.com/mattermost/mattermost/server/v8
Introduced in:
8.0.0-20250731163400-5b955468ea1e Fixed in: 8.0.0-20260506065351-202d125afa87 Fix
go get github.com/mattermost/mattermost/server/v8@v8.0.0-20260506065351-202d125afa87 References
- https://nvd.nist.gov/vuln/detail/CVE-2026-7387 [ADVISORY]
- https://github.com/mattermost/mattermost/pull/36434 [WEB]
- https://github.com/mattermost/mattermost/pull/36432 [WEB]
- https://github.com/mattermost/mattermost/pull/36431 [WEB]
- https://github.com/mattermost/mattermost/pull/36423 [WEB]
- https://github.com/mattermost/mattermost/pull/36316 [WEB]
- https://github.com/mattermost/mattermost/commit/d5f29c8ebbeb04460d16d9e2635ce50deeb78428 [WEB]
- https://github.com/mattermost/mattermost/commit/a9e574a82633915f22071f0d7ca2b006f249ec2a [WEB]
- https://github.com/mattermost/mattermost/commit/8c72083414e675c97987374395e36d1f36b4bd8a [WEB]
- https://github.com/mattermost/mattermost/commit/202d125afa87fe39611686850fd82590c99ca344 [WEB]
- https://github.com/mattermost/mattermost/commit/1ce2484a00c9821ee19708d2c46720e4855033a9 [WEB]
- https://github.com/mattermost/mattermost/releases/tag/v10.11.16 [WEB]
- https://github.com/mattermost/mattermost/releases/tag/v11.5.5 [WEB]
- https://github.com/mattermost/mattermost/releases/tag/v11.6.2 [WEB]
- https://github.com/mattermost/mattermost/releases/tag/v11.7.0 [WEB]
- https://mattermost.com/security-updates [WEB]
- https://github.com/mattermost/mattermost [PACKAGE]