CVE-2020-27481: 
WordPress vulnerability analysis and mitigation

An unauthenticated SQL Injection vulnerability was discovered in Good Layers LMS Plugin versions 2.1.4 and earlier, identified as CVE-2020-27481. The vulnerability exists due to the usage of 'wp_ajax_nopriv' call in WordPress, which allows any unauthenticated user to access the function 'gdlr_lms_cancel_booking' where POST Parameter 'id' was sent directly into SQL query without proper sanitization (NVD, WPScan).

The vulnerability is present in the file 'goodlayers-lms/include/lightbox-form.php' where the function 'gdlr_lms_cancel_booking' processes the 'id' parameter without proper sanitization. The CVSS v3.1 base score is 9.8 (CRITICAL) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. The vulnerability can be exploited via the WordPress admin-ajax.php endpoint (Github POC).

The vulnerability allows attackers to execute arbitrary SQL queries on the affected WordPress installation's database. This could lead to unauthorized access to sensitive information, manipulation of database contents, and potential complete compromise of the WordPress site (NVD).

The vulnerability is easily exploitable through the WordPress admin-ajax.php endpoint without requiring authentication. A proof of concept exists demonstrating the exploitation using a MySQL SLEEP query through a specially crafted POST request (Github POC).

The vulnerability was fixed in version 2.1.5 of the Good Layers LMS Plugin. Users are advised to update to this version or later to protect against this vulnerability (WPScan).