VulnSocial

CVE-2025-12421Disclosure(mattermost / mattermost_server)

LOWCVSS 9.9 · CRITICAL

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to to verify that the token used during the code exchange originates from the same authentication flow, which allows an authenticated user to perform account takeover via a specially crafted email address used when switching authentication methods and sending a request to the /users/login/sso/code-exchange endpoint. The vulnerability requires ExperimentalEnableAuthenticationTransfer to be enabled (default: enabled) and RequireEmailVerification to be disabled (default: disabled).

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0.0/ 10 priority

Sources & remediation

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

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

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

  • 1 mentions across 1 observed day

What's happening

  • 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: 1Technical Details · 2026-03-13: 103-13
Signal classification1 categories
Disclosure
1100.0%
Referenced assets1 URL
Full discourse1 post
  • PulsePatch.io@pulsepatchio
    Disclosure

    A critical token validation bypass (CVE-2025-12421) affects `Mattermost` server. Authenticated users could perform unauthorized actions due to improper token origin verification during code exchange. #Mattermost #Infosec #AuthBypass https://www.pulsepatch.io/posts/cve-2025-12421-mattermost-server-token-validation-bypass

    Post summary

    The post announces a critical token validation bypass (CVE‑2025‑12421) in Mattermost, revealing that authenticated users can perform unauthorized actions due to improper token origin verification during code exchange.

    00000131
    1 followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Appmattermostmattermost_server---

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