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-2020-18
  • Date: 09/22/2020
  • Title: Authentication bypass in SSO endpoint
  • Severity: high
  • Product: Zammad 1.0.x up to 3.4.0
  • Fixed in: Zammad 3.4.1, 3.5.0
  • References:
    --> CVE: Pending

Vulnerability Descriptions

Authentication bypass in SSO endpoint

The SSO endpoint is used to create sessions for requests authenticated by a third party system via SSO. An attacker could send a special header to the SSO endpoint in systems that don't have SSO configured. The request would then create a valid and authenticated session that can be used to perform any actions in the name of other users. However, the user would be notified that a new device performed a login.

Special 🙏 and 🤘 and ❤️ to:

  • N: Dmitry Sobolev
  • D: Security Researcher

It's recommended to update existing Webserver/Reverse Proxies installations that can't be updated automatically.

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:

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