CVE-2026-63206 Zammad: Remote image tracking bypass via shortened URL scheme
Attackers can bypass remote image blocking in Zammad using malformed URLs, silently tracking when and by whom tickets are opened.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-63206?
CVE-2026-63206 is a medium-severity vulnerability in zammad, published on 25 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Which versions are affected by CVE-2026-63206?
How do I fix CVE-2026-63206?
No fix has been published for CVE-2026-63206 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-63206 being exploited?
There is no known exploitation of CVE-2026-63206 in the wild and no public exploit code.
Sources
Also known as GHSA-fpwp-w2p4-hqg7.