Etoile Web Design Ultimate Appointment Booking & Scheduling WordPress Plugin v1.1.9 and lower does not sanitize the value of the “Appointment_ID” GET parameter before echoing it back out inside an input tag. This results in a reflected XSS vulnerability that attackers can exploit with a specially crafted URL.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-24313
Reference (s):
- https://wordpress.org/plugins/ultimate-appointment-scheduling/
- https://zeroaptitude.com/zerodetail/wordpress-plugin-bug-hunting-part-1/