CVE-2026-8143 Booking Calendar – Event Calendar <= 2.1.6 - Unauthenticated Stored Cross-Site Scripting via Multiple Parameters
Unauthenticated attackers can inject arbitrary scripts via specific parameters, leading to script execution when admins view the customer page.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-8143?
CVE-2026-8143 is a high-severity cross-site scripting vulnerability in omnivo Booking Calendar – Event Calendar, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The HBook plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'hb_country_iso', 'hb_usa_state_iso', and 'hb_canada_province_iso' parameters in all versions up to, and including, 2.1.6 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page (the HBook Customers admin page).
Weakness: CWE-79
Which versions are affected by CVE-2026-8143?
How do I fix CVE-2026-8143?
No fix has been published for CVE-2026-8143 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-2026-8143 being exploited?
There is no known exploitation of CVE-2026-8143 in the wild and no public exploit code.
Sources
Also known as GHSA-j6cw-vh4x-xqjh.