9.9

CVE-2025-12419: Account takeover on OAuth/OpenID-enabled servers

Analyzed
AliasesGHSA-3x39-62h4-f8j6GO-2025-4168
Published 27-11-2025Last modified 26-02-2026

Vulnerability summary

CVE-2025-12419 is a critical (CVSS 9.9) vulnerability in mattermost. EPSS estimates a 0.37% chance of exploitation in the next 30 days, higher than 30.5% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.9 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.9/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.37%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:21483-1SUSE-SU-2026:0037-1

Timeline

  1. 27-11-2025
    PublishedVulnerability first disclosed.
  2. 26-02-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.37%

Chance of exploitation in the next 30 days

Percentile

31%

Versus all other CVEs

30-day change

Increase +0.02 pp

From 0.34% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Github.com/mattermost/mattermost-server2 products
  • v5All versions (No fix recorded)
  • v6All versions (No fix recorded)
Mattermost2 products
  • mattermost≥ 10.12.0, ≤ 10.12.1 | ≥ 10.11.0, ≤ 10.11.4 | ≥ 10.5.0, ≤ 10.5.12 | ≥ 11.0.0, ≤ 11.0.3
  • mattermost_server≥ 10.5.0, < 10.5.13 | ≥ 10.11.0, < 10.11.5 | ≥ 10.12.0, < 10.12.2 | ≥ 11.0.0, < 11.0.4
Github.com/mattermost1 product
  • mattermost-server≥ 10.12.0, < 10.12.2 | ≥ 10.11.0, < 10.11.5 | ≥ 10.5.0, < 10.5.13 | ≥ 11.0.0, < 11.0.4 | All versions (No fix recorded)
Github.com/mattermost/mattermost/server1 product
  • v8< 8.0.0-20251028000919-d3ed703dc833

4 vendors · 6 products

References

10 links