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wid-sec-w-2026-0745  ·  Published 2026-03-16  ·  View on BSI CERT-Bund ↗

Mattermost: Multiple Vulnerabilities

CVSS 4.3 MEDIUM

Risk Summary

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to validate team-specific upload_file permissions which allows a guest user to post files in channels where they lack upload_file permission via uploading files in a team where they have permission and reusing the file metadata in a POST request to a different team. Mattermost Advisory ID: MMSA-2025-00553

CVEs (1)

Affected Vendors

Mattermost

Affected Products (18)

Mattermost · Mattermost Server <11.4.0
Mattermost · Mattermost Server 11.4.0
Mattermost · Mattermost Server <11.3.1
Mattermost · Mattermost Server 11.3.1
Mattermost · Mattermost Server <11.2.3
Mattermost · Mattermost Server 11.2.3
Mattermost · Mattermost Server <10.11.11
Mattermost · Mattermost Server 10.11.11
Mattermost · Mattermost Server <11.6.0
Mattermost · Mattermost Server 11.6.0
Mattermost · Mattermost Server <10.11.13
Mattermost · Mattermost Server 10.11.13
Mattermost · Mattermost Server <11.5.1
Mattermost · Mattermost Server 11.5.1
Mattermost · Mattermost Server <11.4.3
Mattermost · Mattermost Server 11.4.3
Mattermost · Mattermost Server <11.3.3
Mattermost · Mattermost Server 11.3.3

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