The NinjaTeam WP Telegram Chat Widget plugin for WordPress suffers from a stored cross-site scripting vulnerability (CWE-79) due to improper neutralization of input during web page generation. Specifically, the 'username' parameter is not properly sanitized or escaped, allowing authenticated users with Contributor-level permissions or higher to inject arbitrary JavaScript code. This malicious code executes in the context of other users who access the injected pages, potentially leading to session hijacking or other client-side attacks. The vulnerability affects all versions up to and including 1.1. The CVSS v3.1 base score is 6.4, reflecting network attack vector, low attack complexity, and limited privileges required.

Successful exploitation allows authenticated users with Contributor or higher privileges to inject persistent malicious scripts into the web pages generated by the plugin. This can lead to client-side code execution in the browsers of users who view the affected pages, potentially resulting in information disclosure or session hijacking. The vulnerability does not impact availability and requires user interaction (viewing the injected page). There are no known active exploits reported.

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 removing the WP Telegram Chat Widget plugin if possible. Monitor official NinjaTeam communications for updates regarding patches or mitigations.