Mattermost erlaubt das Lesen beliebiger Dateien im Zusammenhang mit dem Importieren von Boards in github.com/mattermost/mattermost-server

The Arbitrary File Access vulnerability in Mattermost Server allows an attacker to read files that they should not have access to. This can occur during the board import process. An attacker could leverage this to read configuration files, source code, or other sensitive data stored on the server's file system. The potential impact includes data breaches, intellectual property theft, and potential escalation of privileges if sensitive credentials are exposed. The severity is critical due to the ease of exploitation and the potential for widespread data compromise, particularly in environments where sensitive information is stored on the Mattermost server.

Organizations utilizing Mattermost Server for internal communication and collaboration are at risk, particularly those who allow users to import boards from external sources. Environments with sensitive data stored on the Mattermost server, such as configuration files or credentials, are at heightened risk. Shared hosting environments where multiple Mattermost instances reside on the same server could also be vulnerable.

• go / server:

find /opt/mattermost/data -type f -name '*.json' -print0 | xargs -0 grep -i 'board_import'

• generic web:

curl -I http://your-mattermost-server/api/v4/boards/import | grep -i 'Content-Type:'

1. 2025-03-03Disclosure

   disclosure

1. Reserviert2025-02-18
2. Veröffentlicht2025-03-03
3. Geändert2026-02-04
4. EPSS aktualisiert2026-04-02

The primary mitigation for CVE-2025-25279 is to upgrade Mattermost Server to version 9.11.8+incompatible or later. Before upgrading, it is crucial to review Mattermost's upgrade documentation to ensure compatibility with your existing infrastructure and to avoid potential breaking changes. As a temporary workaround, restrict access to the board import functionality to trusted users only. Monitor Mattermost server logs for any unusual file access attempts. Consider implementing a Web Application Firewall (WAF) with rules to block suspicious file access requests related to board imports.