critical

CVE-2025-12419

Mattermost fails to properly validate OAuth state tokens during OpenID Connect authentication

Published 27 Nov 2025Modified 19 Oct 2026CWE 303

In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

GHSA10.0CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Trivy's own label is CRITICAL. Rated critical by GHSA.

Description

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.

Affected packages and fixed versions

Source	Package	Fixed in
go::GitHub Security Advisory Go	github.com/mattermost/mattermost-server, github.com/mattermost/mattermost/server/v8	10.12.2, 10.11.5, 10.5.13, 11.0.4 and 1 more

Show all 2 entries from 1 source

Source	Package	Fixed in
go::GitHub Security Advisory Go	github.com/mattermost/mattermost-server	10.12.2, 10.11.5, 10.5.13, 11.0.4
go::GitHub Security Advisory Go	github.com/mattermost/mattermost/server/v8	8.0.0-20251028000919-d3ed703dc833

References

All 10 references

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