Mattermost vulnerabilities and fixes

CVEs that mention Mattermost, ranked by priority. 2 tracked.

Mattermost has 2 tracked vulnerabilities, 0 critical. A fixed release or vendor patch exists for 0. Most recent: 2026-10-22. Highest priority: CVE-2026-13411 (score 21/100).

• CVE-2026-13411 MEDIUM 4.3 Mattermost versions 11.7.x <= 11.7.11 fail to validate null elements when decoding playbook import conditions
• CVE-2026-28736 MEDIUM 4.3 DOWNGRADE ** UNSUPPORTED WHEN ASSIGNED ** Focalboard version 8.0 fails to validate file ownership when serving uploaded

FAQ

How do I fix Mattermost vulnerabilities?

Open the CVE for your version, check the affected range, then follow the listed action: upgrade to the fixed release, or downgrade or mitigate if no fix exists yet. Commands for each OS are shown on every CVE page.

Is Mattermost being exploited right now?

None of the tracked Mattermost CVEs are on the CISA Known Exploited Vulnerabilities list at the moment. This is checked every 20 minutes.

Which Mattermost CVE should I patch first?

CVE-2026-13411 currently ranks highest (21/100): Mattermost versions 11.7.x <= 11.7.11 fail to validate null elements when decoding playbook import conditions .

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