The aThemes Starter Sites plugin for WordPress suffers from a stored XSS vulnerability due to improper neutralization of input during web page generation. Specifically, SVG file uploads are not adequately sanitized or escaped, enabling authenticated users with Author-level privileges or above to inject arbitrary JavaScript code. This code executes in the context of users viewing the SVG files, potentially leading to information disclosure or session hijacking. The vulnerability affects all plugin versions up to and including 1.0.53. The CVSS 3.1 base score is 6.4, reflecting network attack vector, low attack complexity, required privileges at the Author level, no user interaction, and impacts on confidentiality and integrity but not availability.

An attacker with Author-level access can inject persistent malicious scripts via SVG file uploads. These scripts execute in the browsers of users who view the SVG files, potentially compromising user data confidentiality and integrity. There is no impact on availability. The vulnerability could facilitate actions such as session hijacking or unauthorized actions performed in the context of affected users.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict Author-level user capabilities to trusted users only and consider disabling SVG uploads if possible. Monitor for updates from the plugin vendor regarding patches or official mitigations.