CVE-2026-56728 Zammad: Cross-User Taskbar Item Access Control Vulnerability
An authenticated user can read another user's taskbar data, including ticket drafts, due to missing authorization checks in the GraphQL API.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-56728?
CVE-2026-56728 is a medium-severity missing authorization vulnerability in zammad, published on 25 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, a broken access control vulnerability exists in Zammad's GraphQL API. An authenticated user can access taskbar item data belonging to another user by crafting a request with the target user's taskbar identifier. The taskbar feature stores transient state for active user sessions, including auto-saved ticket drafts. Under certain conditions, the authorization check for taskbar item access is not enforced, allowing a user to read another user's taskbar item data. This vulnerability is fixed in 7.0.2.
Which versions are affected by CVE-2026-56728?
How do I fix CVE-2026-56728?
No fix has been published for CVE-2026-56728 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-56728 being exploited?
There is no known exploitation of CVE-2026-56728 in the wild and no public exploit code.
Sources
Also known as GHSA-jvcg-5539-vvc3.