CVE-2026-5459

The User Frontend plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'wpuf_payment_method' parameter in all versions up to and including 4.3.12 due to insufficient input sanitization and output escaping. This allows authenticated attackers with subscriber-level access and above to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The bypass technique involves appending a valid gateway keyword such as 'bank' to the HTML payload, causing sanitize_text_field() to yield only the keyword for routing purposes while the full malicious raw value is stored and later rendered unescaped.

The User Frontend WordPress plugin before version 4.3.11 does not enforce its subscription-purchase requirement when processing frontend post submissions, only when rendering the form, allowing unauthenticated users to create and, depending on the form's configuration, immediately publish posts through forms restricted to paying subscribers.

The User Frontend WordPress plugin before 4.3.11 does not prevent user-supplied field values from being deserialized when a submitted post is reopened in its frontend editing form. This allows authenticated users with subscriber-level access and above to perform PHP Object Injection, which may lead to remote code execution when a suitable gadget chain is present on the site.

The User Frontend WordPress plugin before version 4.3.10 does not properly validate field type definitions and deserializes user-controlled post metadata when rendering submitted posts. Users with Editor-level access and above can inject arbitrary PHP objects, which can lead to remote code execution when a suitable POP chain is present on the site.

The User Frontend plugin for WordPress up to version 4.3.7 is vulnerable to Insecure Direct Object Reference (IDOR) via the 'wpuf_files_data' parameter. Missing validation on a user-controlled key allows unauthenticated attackers to overwrite the post_title, post_content, and post_excerpt of any arbitrary post, including administrator posts.

The User Frontend plugin for WordPress up to version 4.3.7 has an authorization bypass vulnerability. Unauthenticated attackers can delete arbitrary media attachments with post_author 0 via the wpuf_file_del AJAX action.