NextGEN Gallery version prior to 4.2.1 are vulnerable to authenticated SQL injection via the 'orderby' parameter on the REST API endpoints '/imagely/v1/galleries' and '/imagely/v1/albums'.

The root cause is an insufficient sanitization function ('cleancolumn()') in the data mapper layer that uses a character blacklist instead of a whitelist approach. This allows an authenticated attacker with the 'NextGEN Gallery overview' capability (assigned to the Administrator role by default) to inject arbitrary SQL into the 'ORDER BY' clause.

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.

Unauthenticated Arbitrary File Download in NextGEN Gallery <= 4.5.0 versions.

The Photo Gallery, Sliders, Proofing and Themes – NextGEN Gallery plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via the 'comment' parameter in all versions up to, and including, 4.5.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Exploitation requires the site to have Shutter or Shutter Reloaded selected as the active lightbox, and the injected comment must be approved through WordPress's standard moderation workflow before the payload is rendered to other visitors.

The Photo Gallery, Sliders, Proofing and Themes – NextGEN Gallery plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to and including 4.2.0. This is due to insufficient object-level authorization in the image deletion REST flow where the permission callback for DELETE /imagely/v1/images/{id} only checks 'NextGEN Manage gallery' permissions and does not enforce gallery ownership or 'NextGEN Manage others gallery' permissions. This makes it possible for authenticated attackers, with Subscriber-level privileges and 'NextGEN Manage gallery' capability, to delete gallery images belonging to other users as well as their associated image files from disk when deleteImg is enabled (default).