Cloudanix VulnDB

CVE-2025-12421

Critical · 9.9

CVSS

9.9

EPSS

0.3%

Published

Nov 27, 2025

CISA due date

—

The record

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).

Affected packages

Ecosystem Package Introduced Fixed
Go github.com/mattermost/mattermost-server 0 No fix
Go github.com/mattermost/mattermost-server 10.11.0 10.11.5
Go github.com/mattermost/mattermost-server 10.12.0 10.12.2
Go github.com/mattermost/mattermost-server 10.5.0 10.5.13
Go github.com/mattermost/mattermost-server 11.0.0 11.0.3
Go github.com/mattermost/mattermost-server/v5 0 No fix
Go github.com/mattermost/mattermost-server/v6 0 No fix
Go github.com/mattermost/mattermost/server/v8 0 8.0.0-20251022210333-acda1fb5dd46
go github.com/mattermost/mattermost-server 10.11.0 10.11.5
go github.com/mattermost/mattermost-server 10.12.0 10.12.2
go github.com/mattermost/mattermost-server 10.5.0 10.5.13
go github.com/mattermost/mattermost-server 11.0.0 11.0.3
openSUSE:Leap 15.6 govulncheck-vulndb 0 0.0.20251230T014957-150000.1.134.1

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