The Power Charts Lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'id' parameter of the [pc] shortcode in all versions up to, and including, 0.1.0. This is due to insufficient input sanitization and output escaping on the 'id' shortcode attribute. Specifically, in the pc_shortcode() function, the 'id' attribute is extracted from user-supplied shortcode attributes and directly concatenated into an HTML div element's class attribute without any escaping or sanitization at line 62. The resulting HTML is then passed through html_entity_decode() before being returned, further undermining any potential safety. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.