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-2021-05
  • Date: 06/08/2020
  • Title: Agent email address is shown to Customer
  • Severity: medium
  • Product: Zammad 1.0.x up to 4.0.0
  • Fixed in: Zammad 4.0.1, 4.1.0
  • References:
    --> CVE: CVE-2021-35301

Vulnerability Descriptions

Agent email address is shown to Customer

Zammad supports communication via different incoming and outgoing channels. Each messages is shown as a different type of article with attributes according to that channel. In certain circumstances the email address of an Agent was shown to a Customer instead of the Email address of the current group the Ticket is in.

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

Together we turn your customers into fans.
Start free trial!
All releases and news directly in your inbox.
Subscribe to the newsletter