Security Advisory


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Security Advisory Details

  • ID: ZAA-2021-04
  • Date: 06/08/2020
  • Title: Incorrect access control for linked Tickets
  • Severity: medium
  • Product: Zammad 1.0.x up to 4.0.0
  • Fixed in: Zammad 4.0.1, 4.1.0
  • References:
    --> CVE: CVE-2021-35302

Vulnerability Descriptions

Incorrect access control for linked Tickets

Zammad comes with a functionality to link Tickets to one another. This enables to create a context of the current topic at hand. While gathering all linked Tickets of the current Ticket the access control was faulty. This way an attacker could see information that should not be accessible.

Special 🙏 and 🤘 and ❤️ to:

This vulnerability is fixed in the latest versions of Zammad and it is recommended to upgrade to one of these.

Fixed releases can be found at:

Additional information

Online version of this advisory:

Send all remarks to security issues to

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