WP ULike Stored Cross-Site Scripting Vulnerability via Shortcode Template Attribute

A stored cross-site scripting vulnerability has been identified in the WP ULike plugin for WordPress, affecting all versions through 5.0.1. The issue arises from the '[wp_ulike_likers_box]' shortcode's 'template' attribute, which is processed by 'html_entity_decode()' without proper output sanitization. This oversight bypasses WordPress's 'wp_kses_post()' content filtering, allowing authenticated attackers with Contributor-level access or higher to inject arbitrary scripts into pages. The injected scripts execute when a user views the affected page, but the corresponding post must have at least one like for the XSS to be triggered.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the page.

Reproduction

To reproduce this vulnerability, an authenticated user with Contributor-level access or higher can use the '[wp_ulike_likers_box]' shortcode and include a script in the 'template' attribute. Once the shortcode is rendered, the injected script will execute when the page is viewed, provided the post has received at least one like.

Remediation

Users are advised to update to WP ULike version 5.0.2, where this vulnerability has been addressed.