CVE-2026-34719

EUVD-2026-20559

08.04.2026, 19:25

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the webhook model was missing a proper validation for loop back addresses, or link-local addresses — only the URL scheme (HTTP/HTTPS) as well as the hostname was checked. This could end up in retrieving confidential metadata of cloud/hosting providers. The existing check is now extended and is applied when configuring webhooks as well as triggering webhook jobs. This vulnerability is fixed in 7.0.1 and 6.5.4.

SSRF

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
GitHub_M	CNA	8.3 HIGH	NETWORK	LOW	HIGH	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:H/SC:L/SI:N/SA:H

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Early Detection

Affected products identified ahead of NVD analysis through intelligence sources.

Vendor	Product	Version	Source
zammad	zammad	𝑥 < 6.5.4	CNA

Common Weakness Enumeration

CWE-918 - Server-Side Request Forgery (SSRF)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

References

https://github.com/zammad/zammad/security/advisories/GHSA-2vgc-vfh2-rw75