VulnSocial

CVE-2025-12419Disclosure(mattermost / mattermost_server)

LOWCVSS 9.9 · CRITICAL

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch mattermost mattermost_server systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD 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.

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0.5/ 10 priority

Sources & remediation

Vendor / third-party advisories
Weakness type (CWE)
CWE-303

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

NONE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • mattermost_server

Threat summary

  • Patch or workaround signal is available
  • 1 mentions across 1 observed day

What's happening

  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 1 signal
  • Disclosure: 1 classified signal
  • 1 total mentions across 1 day

Affected systems

Vendors
mattermost
Products
mattermost_server

Deep dive

Activity timeline1 mentions / 1d
00111Mentions · 2026-03-13: 1Patch / Workaround · 2026-03-13: 1Technical Details · 2026-03-13: 103-13
Signal classification1 categories
Disclosure
1100.0%
Referenced assets1 URL
Full discourse1 post
  • PulsePatch.io@pulsepatchio
    Disclosure

    `Mattermost` (`CVE-2025-12419`) has an authentication bypass flaw via `OAuth` state token validation during `OpenID Connect`. Affects 10.12.1, 10.11.4, 10.5.12, 11.0.3. Patch advised. #Mattermost #AuthBypass #infosec https://www.pulsepatch.io/posts/cve-2025-12419-mattermost-oauth-validation-bypass

    Post summary

    A new authentication bypass flaw (CVE-2025-12419) in Mattermost's OpenID Connect implementation is disclosed, with impacted releases identified and a patch advised.

    00000133
    1 followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Appmattermostmattermost_server---

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