What is CVE-2025-12419?

CVE-2025-12419 is a critical-severity vulnerability in Mattermost, classified under Incorrect Implementation of Authentication Algorithm. CVSS score: 9.9/10. Published 2025-11-27.

How severe is CVE-2025-12419?

Critical severity. CVSS v3 base score is 9.9 out of 10.

Vulnerability in Mattermost

CVE-2025-12419

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 pri…

EPSS: 0.003 (22.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

Affected products

Mattermost — versions 10.12.0, 10.11.0, 10.5.0
Mattermost Mattermost_server

Weakness classification (CWE)

CWE-303 — Incorrect Implementation of Authentication Algorithm

References

responsibledisclosure@mattermost.com (Vendor Advisory)

Frequently asked questions

What is CVE-2025-12419?: CVE-2025-12419 is a critical-severity vulnerability in Mattermost, classified under Incorrect Implementation of Authentication Algorithm. CVSS score: 9.9/10. Published 2025-11-27.
How severe is CVE-2025-12419?: Critical severity. CVSS v3 base score is 9.9 out of 10.