CVE-2024-11855 is a stored cross-site scripting vulnerability in the Koalendar – Easy Appointment Scheduling & Booking Plugin for WordPress, affecting all versions up to and including 1.0.2. The issue is due to improper neutralization of input during web page generation, specifically via the 'height' parameter. Authenticated attackers with Contributor-level privileges or higher can inject arbitrary scripts that execute in the context of users viewing the injected pages. This vulnerability can lead to limited confidentiality and integrity impacts but does not affect availability. The CVSS 3.1 base score is 6.4 (AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N). No patch or vendor advisory is currently provided.

An attacker with Contributor-level or higher access can exploit this vulnerability to inject stored malicious scripts via the 'height' parameter. These scripts execute in the context of users who view the affected pages, potentially leading to limited confidentiality and integrity impacts such as session hijacking or unauthorized actions performed on behalf of users. There is no impact on system availability. No known exploits are reported in the wild.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict Contributor-level access to trusted users only and consider disabling or limiting use of the affected plugin. Monitor for updates from the vendor and apply patches promptly once released.