Executive brief
Meta Box is a WordPress plugin that enables site developers to create custom content fields for posts and media. A flaw in versions before 5.13.1 allows low-privilege users (such as Contributors) to permanently delete media attachments uploaded by other users, even those they have no permission to access. This can destroy important files and break website functionality.
Technical details
The vulnerability is an authorization bypass (broken access control, CWE-862) in the Meta Box plugin's file deletion handler. The plugin fails to verify that a user is authorized to delete a specific attachment before processing the deletion request via the rwmb_delete_file AJAX action. An attacker with low privileges can extract a delete nonce from their own post's file field and replay it with victim attachment IDs and post IDs, bypassing WordPress's native media permissions. The attack requires Meta Box to be installed with at least one file/image field configured, and the attacker to have a user account with Contributor or higher role. The fix is available in version 5.13.1 and later.
Affected products
- Meta Meta Box before 5.13.1
Timeline
- 2026-07-20: disclosed
- 2026-07-20: patched: Version 5.13.1 released
- 2026-08-02: advisory