Medium · published July 31, 2026
WP Photo Album Plus is vulnerable to stored Cross-Site Scripting in all versions up to, and including, 9.2.03.001 through a decode-after-sanitize (double-encoding) flaw in the photo-comment pipeline. On write, `wppa_do_comment()` sanitizes the comment with `wppa_filter_html()` (wp_kses) followed by `wp_strip_all_tags()` (`wppa-functions.php:2623-2624`). Because `wp_strip_all_tags()` only removes *real* tags, an attacker who submits a **double HTML-entity-encoded** payload (e.g. `&lt;img src=... onload=...&gt;`) passes the write filters as harmless entity text and is stored one decode-level down (`<img ... onload=...>`).