CVE-2026-28741: Mattermost doesn't validate CSRF tokens on an authentication endpoint

April 17, 2026 (updated April 29, 2026)

Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to validate CSRF tokens on an authentication endpoint which allows an attacker to update a user’s authentication method via a CSRF attack by tricking a user into visiting a malicious page. Mattermost Advisory ID: MMSA-2026-00625.

References

github.com/advisories/GHSA-m7cf-4gh2-v4qg
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2026-28741

Code Behaviors & Features

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