CVE-2025-12419CRITICAL 9.9EPSS p21.9%
CVE-2025-12419CVE-2025-12419
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.
Scoring
| CVSS 3.1 | 9.9 (CRITICAL) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| EPSS | 0.30% probability of exploitation · percentile 21.9% · 2026-06-19T12:03:05Z |
| Published | 2025-11-27 |
| Last modified | 2025-12-03 |
Underlying weaknesses· 1
References
1
| Type | Target | Confidence | Tier |
|---|---|---|---|
| Weakness | Incorrect Implementation of Authentication Algorithmcwe-303 | 0% | live |
Related by meaning· 6
Nearest entities by semantic similarity across the cs-graph corpus.