Vulnerability · Published May 27, 2026 · Assigned by Wordfence

CVE-2026-8143Booking Calendar – Event Calendar <= 2.1.6 - Unauthenticated Stored Cross-Site Scripting via Multiple Parameters

High 7.2

In plain English

A high-severity cross-site scripting in Booking Calendar – Event Calendar from omnivo. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).

Severity (CVSS 3.1)7.2High

Exploit odds (30 days)0.2%top 91.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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).

Affected products (as reported)

Vendor	Product	Versions
omnivo	Booking Calendar – Event Calendar	0 – through 2.1.6

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

In plain English

Official description

Affected products (as reported)

References