CVE-2025-12421
Published: Nov 27, 2025
Modified: Feb 26, 2026
CVSS v3.1
9.9
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).
| Vendor | Product | Versions |
|---|---|---|
Mattermost | Mattermost | affected 11.0.0 - <= 11.0.2affected 10.12.0 - <= 10.12.1affected 10.11.0 - <= 10.11.4affected 10.5.0 - <= 10.5.12unaffected 11.1.0+4 more versions |
Weaknesses (CWE)
CVSS v3.1 Details
CVSS v3.1 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
References
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