Upstream information

CVE-2025-12421 at MITRE

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).

Other Security Trackers

SUSE information

Overall state of this security issue: Does not affect SUSE products

This issue is currently rated as having critical severity.

CVSS v3 Scores
CVSS detail CNA (Mattermost)
Base Score 9.9
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Changed
Confidentiality Impact High
Integrity Impact High
Availability Impact High
CVSSv3 Version 3.1
No SUSE Bugzilla entries cross referenced.

No SUSE Security Announcements cross referenced.

List of released packages

Product(s) Fixed package version(s) References

SUSE Timeline for this CVE

CVE page created: Thu Nov 27 20:00:17 2025
CVE page last modified: Tue Jan 6 14:31:58 2026