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Vulnerabilities

Vulnerability · 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 wh

Published Nov 27, 2025 · catalog updated Feb 26, 2026 · Mattermost Mattermost

Last checked Oct 26, 2026. A connected source was read within the last 7 days.

Check this week

CVE-2025-12419 is not in CISA KEV. FIRST estimates a 35.00% chance of exploitation in the next 30 days. Check whether you run Mattermost Mattermost.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Critical9.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
35.00%
Remediation
Advisory link
Affected products
vendor Mattermost Mattermost 10.11.0 ≤10.11.4

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Mattermost Mattermost 10.11.0 ≤10.11.410.11.0 ≤10.11.4

How to fix CVE-2025-12419

  • No stored fix

    No vendor fix text is stored. Use the linked advisory before you change production.

  • Version check

    Seen in 10.11.0 ≤10.11.4

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2025-12419 is not in CISA KEV. FIRST estimates a 35.00% chance of exploitation in the next 30 days. Check whether you run Mattermost Mattermost.

Which versions are affected?

Compare what you have installed with Mattermost Mattermost 10.11.0 ≤10.11.4 10.11.0 ≤10.11.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 35.00%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 27, 2025 · EUVD

    Detected

    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 (de

  2. Feb 26, 2026 · EUVD

    Updated

    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 (de

Sources

  • EUVDVulnerability recordEUVD-2025-199827

    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 m

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Feb 26, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • EUVDOct 26, 2026