CVE-2026-34720 Zammad has an origin validation error in SSO mechanism
Attackers can bypass SSO authentication by spoofing headers, potentially gaining unauthorized access to user accounts in Zammad helpdesk systems.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-34720?
CVE-2026-34720 is a low-severity authentication bypass vulnerability in Zammad Zammad, published on 8 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-346
Which versions are affected by CVE-2026-34720?
It affects 1 product.
Products include Zammad Zammad.
How do I fix CVE-2026-34720?
No fix has been published for CVE-2026-34720 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-34720 being exploited?
There is no known exploitation of CVE-2026-34720 in the wild and no public exploit code.
Other vulnerabilities in Zammad Zammad
Sources
Also known as GHSA-hcv6-w4h9-p2p7.