The WP Photo Album Plus plugin for WordPress is vulnerable to authenticated Command Injection in all versions up to, and including, 9.3.02.002 via the value parameter of the update-photo AJAX action. This is due to insufficient shell escaping within the wppa_image_magick_a() function, where the attacker-controlled value parameter is concatenated raw — without escapeshellarg() — into an ImageMagick command string before being passed to exec(); further, wppa_decode() actively restores percent-encoded shell metacharacters (e.g., %26→&, %23→#) rather than stripping them, allowing crafted payloads to survive sanitization and break out of the ImageMagick argument context. This makes it possible for authenticated attackers holding the plugin-defined wppa_upload capability to execute arbitrary operating-system commands as the web-server user, achieving full remote code execution on the underlying server. Exploitation requires ImageMagick to be enabled on the server; the wppa_upload capability is a plugin-level privilege that site administrators may grant to lower-privileged WordPress roles via the plugin's Users settings, broadening the pool of potential attackers beyond administrators.