Enhance SQL injection protection in regex patterns

Updated regular expressions to strengthen protection against sleep and benchmark injection attacks. This change improves the security of queries by handling potential edge cases more effectively.

includes/core/class-member-directory.php

@@ -1710,7 +1710,8 @@ if ( ! class_exists( 'um\core\Member_Directory' ) ) {
 			$regexp_map = array(
 				'/select(.*?)from/im',
 				'/select(.*?)sleep/im',
-				"/sleep\(\d+\)/im", // avoid any sleep injections
+				"/sleep\(\s*[\"'`]?\s*\d+\s*[\"'`]?\s*\)/im", // avoid any sleep injections
+				"/benchmark\(\s*[\"'`]?\s*\d+\s*[\"'`]?\s*,.*\)/im", // avoid any benchmark injections
 				'/select(.*?)database/im',
 				'/select(.*?)where/im',
 				'/update(.*?)set/im',