LearnDash LMS <= 5.1.5 - Authenticated (Subscriber+) Arbitrary File Upload via Assignment Upload Handler

The LearnDash LMS plugin for WordPress is vulnerable to Unrestricted File Type Upload in versions up to and including 5.1.5. This is due to insufficient input validation in the 'learndash_fileupload_process' function, which iterates through an entire array and validates only the first file. This makes it possible for authenticated attackers, with subscriber-level access and above who are enrolled in a course with assignment uploads enabled, to upload arbitrary disallowed files, including PHP files, to the server's wp-content/uploads/learndash/assignments/ directory. The uploaded files can only be used for Remote Code Execution if default server configurations have been changed to allow for execution.

An attacker needs Subscriber access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: LearnDash LMS 5.1.5.1 closes this, and updating the plugin is the step that ends it.

• Firewall
• Scanner
• Alerts