CVE-2025-12419

Name: CVE-2025-12419
Creator: NVD / NIST
Published: 2025-11-27T16:15:46.957+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.9/10EPSS 0.30%

Last modified Jun 17, 2026

CVE-2025-12419 is a critical-severity vulnerability rated 9.9/10 on the CVSS scale. 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.. EPSS estimates a 0.30% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.9/10

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

EPSS Probability

0.30%

22.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-303

Affected Software

Vendor	Product	Versions
Mattermost	Mattermost Server	>= 10.5.0, < 10.5.13
Mattermost	Mattermost Server	>= 10.11.0, < 10.11.5
Mattermost	Mattermost Server	>= 10.12.0, < 10.12.2
Mattermost	Mattermost Server	>= 11.0.0, < 11.0.4

References

https://mattermost.com/security-updatesVendor Advisory

Timeline

Published: Nov 27, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-12419?

How severe is CVE-2025-12419?

CVE-2025-12419 has a CVSS score of 9.9/10 (CRITICAL severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.

How do I fix CVE-2025-12419?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-12419?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST