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Medium · 5.3 CVE-2026-34718 EUVD-2026-20558

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

Published Apr 8, 2026 · Updated Apr 8, 2026 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
zammad zammad < 6.5.4, >= 7.0.0-alpha, < 7.0.1 —

Advisories 1

References