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Medium WID-SEC-2026-1650 6 CVEs

Mattermost (Desktop, Server und Mobile): Mehrere Schwachstellen

Published May 21, 2026 · Updated Jun 22, 2026 · Revision 2 · de-DE

Vendor: Mattermost Product: Mattermost Platform: Linux Platform: Windows

Summary

Ein Angreifer kann mehrere Schwachstellen in Mattermost ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen und um Informationen offenzulegen.

Product

Mattermost ist ein webbasierter Instant-Messaging-Dienst.

Vulnerabilities 6

  • Medium 6.4
    CVE-2026-6062

    IDOR in Jira plugin subscription edit endpoint

    Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels the…

    Mattermost Mattermost github.com/mattermost/mattermost-server Go
  • Medium 6.4
    CVE-2026-6673

    Mattermost Jira plugin had unauthenticated {{/ac/installed}} lifecycle callback during pending Jira Cloud install

    Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integratio…

    Mattermost Mattermost github.com/mattermost/mattermost-server Go
  • Medium 6.1
    CVE-2026-22880

    Mobile SSO authentication flow allows credential theft via malicious server

    Mattermost Mobile Apps versions <=2.37 11.4 2.0.37 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to properly validate the SSO authentication callback origin which allows an attacker controlling a malicious Mattermost server to steal user credentials for a legitimate M…

    Mattermost Mattermost
  • Medium 5.4
    CVE-2026-5139

    GitLab Plugin Allows Non-Admin Users to Modify Default Instance Configuration

    Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to…

    Mattermost Mattermost github.com/mattermost/mattermost-server Go
  • Medium 4.3
    CVE-2026-9162

    Global session revocation does not invalidate active WebSocket connections

    Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to invalidate cached authentication state for active WebSocket connections during global session revocation, which allows a user with an existing WebSocket conn…

    Mattermost Mattermost github.com/mattermost/mattermost-server Go
  • Low 3.8
    CVE-2026-8074

    Improper Permission Check Allows User Manager to Deactivate Bot Accounts

    Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to enforce bot-specific permission checks on the user active status endpoint, which allows a User Manager with user management write access but no Integrations access to deactivate bot accounts vi…

    Mattermost Mattermost github.com/mattermost/mattermost-server Go

Revision history

  1. #2

    CVE's ergänzt

  2. #1

    Initiale Fassung

References