CVE-2025-12421

Description

Mattermost fails to to verify the token used during code exchange in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: github.com/mattermost/mattermost-server from v10.5.0 before v10.5.13, from v10.11.0 before v10.11.5, from v10.12.0 before v10.12.2, from v11.0.0 before v11.0.3.

How to fix CVE-2025-12421

To remediate CVE-2025-12421, upgrade the affected package to a fixed version below.

• —upgrade to 11.0.3 or later
• —no fix listed
• —no fix listed
• —no fix listed
• —upgrade to 8.0.0-20251022210333-acda1fb5dd46 or later
• —upgrade to 8.0.0-20251022210333-acda1fb5dd46 or later

Is CVE-2025-12421 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (6)

• >= 11.0.0, < 11.0.3
• from 0
• from 0
• from 0
• from 0, < 8.0.0-20251022210333-acda1fb5dd46
• from 0, < 8.0.0-20251022210333-acda1fb5dd46

CVSS scores

References (8)

• ADVISORYgithub.com/advisories/GHSA-mp6x-97xj-9x62
• ADVISORYnvd.nist.gov/vuln/detail/CVE-2025-12421
• PATCHgithub.com/mattermost/mattermost
• WEBgithub.com/mattermost/mattermost/commit/5072bbf689a46b3b97b2373f26149f5891396e6b