CVE-2026-34718 PUBLISHED

Zammad improperly neutralizes of script-related HTML tags in ticket articles

Assigner: GitHub_M
Reserved: 30.03.2026 Published: 08.04.2026 Updated: 08.04.2026

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the HTML sanitizer for ticket articles was missing proper sanitization of data: ... URI schemes, resulting in storing such malicious content in the database of the Zammad instance. The Zammad GUI is rendering this content, due to applied CSP rules no harm was done by e.g., clicking such a link. This vulnerability is fixed in 7.0.1 and 6.5.4.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS Score: 5.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	zammad
Product	zammad
Versions	Version < 6.5.4 is affected Version >= 7.0.0-alpha, < 7.0.1 is affected

References

https://github.com/zammad/zammad/security/advisories/GHSA-c2cf-9fc7-jhf3

Problem Types

CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) CWE