CVE-2026-34720: Zammad has an origin validation error in SSO mechanism
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the SSO mechanism in Zammad was not verifying the header originates from a trusted SSO proxy/gateway before applying further actions on it. This vulnerability is fixed in 7.0.1 and 6.5.4.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Zammadto a version that resolves this vulnerability.Fixed in 7.0.1 - Upgrade
Upgrade
Zammadto a version that resolves this vulnerability.Fixed in 6.5.4
Event History
Frequently Asked Questions
What is the severity of CVE-2026-34720?
CVE-2026-34720 has been assigned a high severity due to the potential for unauthorized access through insecure single sign-on (SSO) validation.
How do I fix CVE-2026-34720?
To fix CVE-2026-34720, upgrade Zammad to version 7.0.1 or 6.5.4 or later where the SSO mechanism's origin validation issue is resolved.
What versions of Zammad are affected by CVE-2026-34720?
CVE-2026-34720 affects Zammad versions prior to 7.0.1 and 6.5.4.
What impact does CVE-2026-34720 have on my Zammad installation?
CVE-2026-34720 can allow malicious actors to exploit the SSO mechanism and gain unauthorized access to the system.
Is there a workaround for CVE-2026-34720?
A temporary workaround for CVE-2026-34720 involves reviewing and manually validating SSO headers before processing them, but upgrading is strongly recommended.