# CERT-FR Flags Mattermost Server Vulnerabilities

Published: 2026-10-21 · Severity: routine · Sectors: Technology · Not tied to an actor or CVE
Canonical: https://vorant.io/reports/7127a890-ec47-5757-9e80-a438be610458/cert-fr-flags-mattermost-server-vulnerabilities
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> CERT-FR advises multiple unspecified vulnerabilities in Mattermost Server versions before 11.7.13, 11.10.3, and 11.11.2; patches available.

Source: cert.ssi.gouv.fr — https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-1348

## What to check

- Applies to: Not tied to a specific actor, malware or CVE, only to the sectors it covers, so it may be general reporting. Check the source before acting on it. Whether it concerns you is not assessed.

CERT-FR issued an advisory regarding multiple vulnerabilities in Mattermost Server, a widely used team collaboration platform. The affected versions include 11.7.x prior to 11.7.13, 11.10.x prior to 11.10.3, and 11.11.x prior to 11.11.2. The vendor has not specified the exact nature of the security impact, and CERT-FR's advisory does not detail the risk level beyond noting it is unspecified by the publisher.

Defenders running Mattermost Server should consult the vendor's security bulletins (MMSA-2026-00772 and MMSA-2026-00783, both dated 20 October 2026) for full technical details and apply the available patches promptly. No indication of active exploitation is given in this advisory; organizations should treat this as a routine patch management item and upgrade to the fixed versions as soon as feasible.

Source reporting: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-1348

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