Security Advisory


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Security Advisory Details

  • ID: ZAA-2020-21
  • Date: 09/22/2020
  • Title: Stored XSS in Tags element
  • Severity: medium
  • Product: Zammad 1.0.x up to 3.4.0
  • Fixed in: Zammad 3.4.1, 3.5.0
  • References:
    --> CVE: 2020-26035

Vulnerability Descriptions

Stored XSS in Tags element

Zammad comes with a functionality to add Tags to Tickets. Added Tags are shown to the Agent in the Ticket view. However, when rendering the Tags no proper quoting is in place so the raw text is added to the DOM and rendered. This allows an attacker to store malicious code to a Ticket that will be evaluated when opening a Ticket.

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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