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CVE-2025-12421

CRITICAL
9.9
CVSS 3.1
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).

Metadata

CVE ID
CVE-2025-12421
State
PUBLISHED
Assigner
Mattermost
Reserved
2025-10-28 16:54 UTC
Published
2025-11-27 17:47 UTC
Last updated
2026-02-26 16:07 UTC
Primary CWE
CWE-303
CWE-303: Incorrect Implementation of Authentication Algorith…
Vendor / Product
Mattermost / Mattermost
Sources
cve.org  ·  NVD

Severity & Metrics

9.9 CRITICAL CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
SSVC — CISA Coordinator
Exploitation
none
Automatable
no
Tech. Impact
total
Affected products (1)
VendorProductPlatformVersions
Mattermost Mattermost — 11.0.0 ≤ 11.0.2, 10.12.0 ≤ 10.12.1, 10.11.0 ≤ 10.11.4, 10.5.0 ≤ 10.5.12 …
Weakness (CWE)
CWESourceDescription
CWE-303 cna CWE-303: Incorrect Implementation of Authentication Algorithm
CVSS scores (1)
ScoreSeverityVersionSourceVector
9.9 CRITICAL 3.1 cna CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
References (1)
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