CVE-2026-76010: Photo Gallery, Sliders, Proofing and Themes – NextGEN Gallery <= 4.4.1 - Authenticated (Custom+) Remote Code Execution via XML-RPC 'meta_data' Mass Assignment and Path Traversal

The Photo Gallery, Sliders, Proofing and Themes – NextGEN Gallery plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 4.4.1 via the renderimage function. This is due to unrestricted mass assignment of caller-supplied metadata keys onto the image model combined with missing realpath containment in path construction and a bypassable signature check on the public image delivery route. This makes it possible for authenticated attackers, with custom-level access and above, to execute code on the server. Exploitation requires the authenticated attacker to own at least one NextGEN gallery — a condition that can be satisfied by any Subscriber who was ever granted the 'NextGEN Manage gallery' capability, and that access is retained indefinitely due to the stored gallery-author equality fallback in canmanagegallery() even after the capability is revoked.