Go/github.com/mattermost/mattermost/server/v8 CVE-2026-25783: medium 4.3, EPSS 0.30%

Mattermost fails to properly validate User-Agent header tokens in github.com/mattermost/mattermost-server

Action: Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20260129181235-1346cf529aef or later.

go get github.com/mattermost/mattermost/server/v8@v8.0.0-20260129181235-1346cf529aef

Affected

Fixed versions

Sources

• osv: GO-2026-4725#Go/github.com/mattermost/mattermost/server/v8
• nvd: CVE-2026-25783
• https://github.com/advisories/GHSA-2v3w-6g35-5f9v
• https://github.com/mattermost/mattermost/commit/1346cf529aef0672c39a56ec10d1b8a9c8fb387d
• https://mattermost.com/security-updates

CVE-2026-25783 · published 2026-03-26T20:33:02Z · modified 2026-03-26T21:03:22.280226Z · JSON