The Booking Calendar and Booking Calendar Pro plugins for WordPress contain a reflected XSS vulnerability via the 'calendar_id' parameter due to improper input neutralization. This allows unauthenticated attackers to inject arbitrary web scripts that execute when a user interacts with a maliciously crafted link. The issue affects all versions up to and including 3.2.19 and 11.2.19 respectively. The CVSS 3.1 base score is 6.1 (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N), reflecting network attack vector, low attack complexity, no privileges required, user interaction required, scope changed, and low impact on confidentiality and integrity with no impact on availability. No known exploits in the wild have been reported, and no patch or vendor advisory is provided in the data.

Successful exploitation can lead to execution of arbitrary scripts in the context of the affected website, potentially allowing attackers to steal user session data or perform actions on behalf of the user. The impact is limited to confidentiality and integrity with no availability impact. The vulnerability requires user interaction and is exploitable remotely without authentication.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should exercise caution with untrusted links that include the 'calendar_id' parameter. Monitoring vendor channels for updates is recommended.