CVE-2025-13821

Description

Mattermost fails to sanitize sensitive data in WebSocket messages 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/v5 before v5.3.2-0.20251210191531-cd17b61de41b.

How to fix CVE-2025-13821

To remediate CVE-2025-13821, upgrade the affected package to a fixed version below.

• —no fix listed
• —no fix listed
• —no fix listed
• —no fix listed
• —upgrade to 8.0.0-20251210191531-cd17b61de41b or later
• —upgrade to 8.0.0-20251210191531-cd17b61de41b or later

Is CVE-2025-13821 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (6)

• >= 11.1.0
• from 0
• from 0
• from 0
• from 0, < 8.0.0-20251210191531-cd17b61de41b
• from 0, < 8.0.0-20251210191531-cd17b61de41b

CVSS scores

References (5)

• ADVISORYgithub.com/advisories/GHSA-pp9j-pf5c-659x
• ADVISORYnvd.nist.gov/vuln/detail/CVE-2025-13821
• PATCHgithub.com/mattermost/mattermost
• WEBgithub.com/mattermost/mattermost/commit/cd17b61de41bf0a49b524bb91ce0bbe859e5a100
• WEB