The Happy Addons for Elementor plugin suffers from a stored XSS vulnerability (CWE-79) due to improper neutralization of input during web page generation. Specifically, the Calendly widget does not adequately sanitize or escape user-supplied attributes, enabling authenticated users with contributor or higher privileges to inject arbitrary JavaScript code. This code executes in the context of any user who visits the compromised page, potentially leading to session hijacking or other script-based attacks. The vulnerability affects all plugin versions up to 3.10.5. No known exploits in the wild have been reported, and no patch or remediation details are currently provided by the vendor.

An attacker with contributor-level or higher access can inject persistent malicious scripts into pages using the vulnerable Calendly widget. These scripts execute in the browsers of users who view the infected pages, potentially allowing theft of session tokens, defacement, or other client-side attacks. The vulnerability does not affect availability but impacts confidentiality and integrity. The CVSS 3.1 base score is 6.4 (medium severity), reflecting network attack vector, low attack complexity, required privileges, no user interaction, and partial impact on confidentiality and integrity.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, restrict contributor-level access to trusted users only and consider disabling or removing the Calendly widget functionality in the plugin to prevent exploitation. Monitor for updates from the vendor or WordPress plugin repository regarding patches or security updates.