Mattermost Server 10.11.x < 10.11.16 / 11.5.x < 11.5.5 / 11.6.x < 11.6.2 Multiple Vulnerabilities (MMSA-2026-00616 / MMSA-2026-00649 / MMSA-2026-00655 / MMSA-2026-00656 / MMSA-2026-00661 / MMSA-2026-00662 / MMSA-2026-00665)

The version of Mattermost Server installed on the remote host is affected by multiple vulnerabilities: - Mattermost fails to require role-management authorization when setting the schemeadmin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to...

CVE-2026-6961

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations...

EUVD-2026-36504

Mattermost versions 11.6.x = 11.6.1, 11.5.x = 11.5.4, 10.11.x = 10.11.15, 10.11.x = 10.11.16 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations...

PT-2026-48939

Name of the Vulnerable Software and Affected Versions Mattermost versions 11.6.0 through 11.6.1 Mattermost versions 11.5.0 through 11.5.4 Mattermost versions 10.11.0 through 10.11.16 Description Insufficient sanitization of the FileInfo.Name variable received from federated peers during shared...