Independent Analytics <= 2.15.0 - Unauthenticated Stored Cross-Site Scripting

The Independent Analytics plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 404 not_found_url tracking parameter in versions up to, and including, 2.15.0. This is due to the get_cell_content() function applying urldecode() after esc_url() when rendering the URL column for 404 entries — a sequence that allows percent-encoded HTML to pass URL validation and then be reconstructed as raw markup, which wp_kses_post() does not strip because it retains img elements and data-* attributes, and because the public REST endpoint /iawp/search accepts unauthenticated requests as long as they carry a signature that is itself embedded in public page HTML. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.