Security Advisory


· Please read carefully and check if the version of your Zammad system is affected by this vulnerability. Please send us information regarding vulnerabilities in Zammad!

Security Advisory Details

  • ID: ZAA-2020-24
  • Date: 11/16/2020
  • Title: Incorrect Access Control when updating Articles via the REST API
  • Severity: medium
  • Product: Zammad 1.0.x up to 3.5.0
  • Fixed in: Zammad 3.5.1, 3.6.0
  • References:
    --> CVE: 2020-29160

Vulnerability Descriptions

Incorrect Access Control when updating Articles via the REST API

Zammad comes with a functionality to update the State of a Ticket Article from external to internal and vice versa. Other from that it's not possible to update an Article via the WebApp. However, it's possible to update any Article attribute via the REST API for any User with access to the Ticket e.g. regular Agents, User who created the Article. This violates audit-proof principle that Zammad has.

Recommended Resolution

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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