CVE-2025-12419: Mattermost fails to properly validate OAuth state tokens during OpenID Connect authentication
(updated )
Mattermost versions 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12, 11.0.x <= 11.0.3 fail to properly validate OAuth state tokens during OpenID Connect authentication which allows an authenticated attacker with team creation privileges to take over a user account via manipulation of authentication data during the OAuth completion flow. This requires email verification to be disabled (default: disabled), OAuth/OpenID Connect to be enabled, and the attacker to control two users in the SSO system with one of them never having logged into Mattermost.
References
- github.com/advisories/GHSA-3x39-62h4-f8j6
- github.com/mattermost/mattermost
- github.com/mattermost/mattermost/commit/15364790cc277cfaa372693d2d5442b87f70fd42
- github.com/mattermost/mattermost/commit/364c2203de00fe0d8424b6b46d6f0eeb02a2539a
- github.com/mattermost/mattermost/commit/46b5c436bb3093cc1da3fa2455f93d4c52389eee
- github.com/mattermost/mattermost/commit/c3f4818afe46a7084740e809708ae22641c76d8d
- github.com/mattermost/mattermost/commit/d3ed703dc8330684952eb8d49a375bac6ea7b0c6
- github.com/mattermost/mattermost/pull/34296
- mattermost.com/security-updates
- nvd.nist.gov/vuln/detail/CVE-2025-12419
Code Behaviors & Features
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