CVE-2026-77506 Cross-site scripting in Znuny
An attacker can inject malicious scripts via the AgentTicketEmailResend template in Znuny, potentially leading to session hijacking or code execution.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-77506?
CVE-2026-77506 is a medium-severity cross-site scripting vulnerability in Znuny, published on 20 Aug 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
Znuny before LTS 6.5.22 allows AgentTicketEmailResend template XSS.
Weakness: CWE-79
Which versions are affected by CVE-2026-77506?
How do I fix CVE-2026-77506?
Upgrade to a fixed version.
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-2026-77506 being exploited?
There is no known exploitation of CVE-2026-77506 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-77506, GHSA-4mvf-wmjf-gpfv, UBUNTU-CVE-2026-77506.