CVE-2026-17089 Events Manager <= 7.4.0.1 - Reflected Cross-Site Scripting via 'header_format' Parameter
Unauthenticated attackers can inject arbitrary scripts via the header_format parameter in the Events Manager WordPress plugin, potentially executing code in victim browsers.
- 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-2026-17089?
CVE-2026-17089 is a medium-severity cross-site scripting vulnerability in netweblogic Events Manager – Calendar, Bookings, Tickets, and more!, published on 25 Aug 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
The Events Manager – Calendar, Bookings, Tickets, and more! plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'header_format' parameter in all versions up to, and including, 7.4.0.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. The shortcode entry point sanitizes 'header_format' via wp_kses(), but the unauthenticated 'search_events_grouped' AJAX action bypasses this sanitization entirely, leaving the parameter unsanitized before it is echoed into the HTML body in output_grouped().
Weakness: CWE-79
Which versions are affected by CVE-2026-17089?
How do I fix CVE-2026-17089?
No fix has been published for CVE-2026-17089 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-2026-17089 being exploited?
There is no known exploitation of CVE-2026-17089 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-gg76-jx66-hjq8.