Improper input validation in Zammad
CVE-2026-63206
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.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
EPSS exploit prediction
EPSS: 0.003 (20.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Zammad — versions < 7.1.2