CVE-2026-84463 Cross-site scripting in zammad
Attackers with KB editing rights can inject HTML to force session switching, allowing unauthorized access to other user accounts.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-84463?
CVE-2026-84463 is a medium-severity cross-site scripting vulnerability in zammad, published on 25 Sep 2026. Any signed-in user can exploit it over the network, 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, a user with Knowledge Base editing rights for a category can embed a video widget in a published answer with a specially crafted value. When the answer is rendered, that value is inserted into the page's HTML without being escaped for its attribute context, allowing it to break out and inject additional HTML into the page. When another user who has permission to switch between user sessions views the affected answer, the injected HTML causes their browser to silently send a request to Zammad's session-switching endpoint using their own active credentials. This results in switching their session to an account chosen by the person who wrote the Knowledge Base answer. No action is required from the viewer beyond opening the published answer. This issue is fixed in version 7.1.2.
Which versions are affected by CVE-2026-84463?
How do I fix CVE-2026-84463?
No fix has been published for CVE-2026-84463 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-84463 being exploited?
There is no known exploitation of CVE-2026-84463 in the wild and no public exploit code.
Sources
Also known as GHSA-cxjg-4gmf-5xqc.