{"id":"CVE-2025-12421","details":"Mattermost versions 11.0.x \u003c= 11.0.2, 10.12.x \u003c= 10.12.1, 10.11.x \u003c= 10.11.4, 10.5.x \u003c= 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).","aliases":["GHSA-mp6x-97xj-9x62","GO-2025-4170"],"modified":"2026-04-09T10:33:43.628775Z","published":"2025-11-27T18:15:46.223Z","related":["SUSE-SU-2026:0037-1"],"references":[{"type":"ADVISORY","url":"https://mattermost.com/security-updates"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost/mattermost-server","events":[{"introduced":"58bd34fd34cbd7d3da777d627b6cffdf8a532930"},{"fixed":"288281e8cbf15260ad074b883a263b796cdb3e28"},{"introduced":"5b955468ea1ea8b56c0fb10feb258a36a767d7bb"},{"fixed":"46b5c436bb3093cc1da3fa2455f93d4c52389eee"},{"introduced":"ba3dc1612ce8f37bf9814b1ea6364181fb5abd62"},{"fixed":"364c2203de00fe0d8424b6b46d6f0eeb02a2539a"},{"introduced":"0"},{"fixed":"feb598ed2b7ac3cb78a253b032ad7e4628b0de00"}],"database_specific":{"versions":[{"introduced":"10.5.0"},{"fixed":"10.5.13"},{"introduced":"10.11.0"},{"fixed":"10.11.5"},{"introduced":"10.12.0"},{"fixed":"10.12.2"},{"introduced":"11.0.0"},{"fixed":"11.0.3"}]}}],"versions":["@mattermost/client@10.11.0","@mattermost/client@10.12.0","@mattermost/client@10.5.0","@mattermost/types@10.11.0","@mattermost/types@10.12.0","@mattermost/types@10.5.0","cloud-2022-07-20-1","cloud-2022-08-10-1","cloud-2022-09-08-1","cloud-2022-10-06-1","cloud-2022-11-11-1","cloud-2022-11-24-1","mattermost-redux@10.11.0","mattermost-redux@10.12.0","preview-v0.1","server/public/v0.0.10","server/public/v0.0.11","server/public/v0.0.12","server/public/v0.0.13","server/public/v0.0.14","server/public/v0.0.15","server/public/v0.0.16","server/public/v0.0.17","server/public/v0.0.18","server/public/v0.0.5","server/public/v0.0.6","server/public/v0.0.7","server/public/v0.0.8","server/public/v0.0.9","server/public/v0.1.0","server/public/v0.1.1","server/public/v0.1.10","server/public/v0.1.11","server/public/v0.1.12","server/public/v0.1.13","server/public/v0.1.14","server/public/v0.1.15","server/public/v0.1.16","server/public/v0.1.17","server/public/v0.1.18","server/public/v0.1.19","server/public/v0.1.2","server/public/v0.1.3","server/public/v0.1.4","server/public/v0.1.5","server/public/v0.1.6","server/public/v0.1.7","server/public/v0.1.8","server/public/v0.1.9","v0.5.0","v10.11.0","v10.11.0-rc3","v10.11.1","v10.11.1-rc1","v10.11.2","v10.11.2-rc1","v10.11.2-rc2","v10.11.3","v10.11.4","v10.11.4-rc1","v10.11.4-rc2","v10.11.4-rc3","v10.12.0","v10.12.1","v10.12.1-rc1","v10.5.0","v10.5.0-rc6","v10.5.1","v10.5.1-rc1","v10.5.1-rc2","v10.5.10","v10.5.10-rc1","v10.5.10-rc2","v10.5.11","v10.5.11-rc1","v10.5.12","v10.5.12-rc1","v10.5.2","v10.5.3","v10.5.3-rc1","v10.5.4","v10.5.4-rc1","v10.5.4-rc2","v10.5.5","v10.5.5-rc1","v10.5.6","v10.5.6-rc1","v10.5.7","v10.5.8","v10.5.8-rc1","v10.5.9","v10.5.9-rc1","v10.5.9-rc2","v10.5.9-rc3","v10.5.9-rc4","v11.0.0-alpha.1","v11.0.1","v11.0.1-rc1","v11.0.1-rc2","v11.0.1-rc3","v11.0.2","v11.0.3-rc1","v4.10.0-rc1","v4.2.0-rc1","v4.3.0-rc1","v4.4.0-rc1","v4.5.0-rc1","v4.6.0-rc1","v4.6.0-rc2","v4.7.0-rc1","v4.8.0-rc1","v4.9.0-rc1","v5.0.0-rc1","v5.1.0-rc1","v5.2.0-rc1","v5.2.0-rc2"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-12421.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"}]}