MEDIUM4.3

GO-2026-5512

Mattermost allows authenticated guest users to enumerate user IDs outside their allowed visibility scope in github.com/mattermost/mattermost-server

Quick fix

GO-2026-5512 — github.com/mattermost/mattermost-server: upgrade to the fixed version with the command below.

go get github.com/mattermost/mattermost-server@v10.11.11+incompatible

Details

Mattermost allows authenticated guest users to enumerate user IDs outside their allowed visibility scope in github.com/mattermost/mattermost-server

Enter the version of the package you're using.

Introduced in: 10.11.0-rc1+incompatibleFixed in: 10.11.11+incompatible

Fixgo get github.com/mattermost/mattermost-server@v10.11.11+incompatible

Introduced in: 0

No fixed version published yet for github.com/mattermost/mattermost-server/v5 (go modules). Pin to a known-safe version or switch to an alternative.

Introduced in: 0

No fixed version published yet for github.com/mattermost/mattermost-server/v6 (go modules). Pin to a known-safe version or switch to an alternative.

Introduced in: 8.0.0-20260105080200-d27a2195068dFixed in: 8.0.0-20260217110922-b7d4a1f1f59b

Fixgo get github.com/mattermost/mattermost/server/v8@v8.0.0-20260217110922-b7d4a1f1f59b