Vulnerability · Published Sep 25, 2026 · Assigned by GitHub_M
CVE-2026-63206Zammad: Remote image tracking bypass via shortened URL scheme
Medium 5.3
In plain English
A medium-severity improper input validation in zammad from zammad. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities).
Official description
Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, zammad's HTML sanitizer, which blocks remote images in ticket articles and email views, can be bypassed using a shortened URL format that omits the double slash after the scheme (for example a shortened HTTP URL instead of a shortened HTTP URL). Modern browsers treat both forms as equivalent remote URLs. As a result, an attacker who sends a crafted email or ticket can cause the recipient's browser to silently load an image from an external server, revealing when and by whom the ticket was opened. Zammad's "remote content blocked" warning is not shown because the sanitizer does not recognize the shortened form as remote. This issue is fixed in version 7.1.2.
Affected products (as reported)
Weakness: CWE-20, CWE-184 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N