diff -Nur --no-dereference phpki-ng.old/phpki-ng-0.84/ns_revoke_query.php phpki-ng/phpki-ng-0.84/ns_revoke_query.php
--- phpki-ng.old/phpki-ng-0.84/ns_revoke_query.php	2022-11-18 14:43:19.940000000 -0500
+++ phpki-ng/phpki-ng-0.84/ns_revoke_query.php	2022-12-14 16:49:46.524000000 -0500
@@ -16,13 +16,16 @@
 #
 include('./config.php');
 include(STORE_DIR.'/config/config.php');
-
-$serial = escapeshellcmd(trim($_SERVER['QUERY_STRING']));
+$serial=trim($_SERVER['QUERY_STRING']);
+if ( ! is_numeric($serial) ) {
+    # if it is not a numerical serial, then it is not revoked!
+    print '0';
+    exit;
+}
+$serial = escapeshellcmd($serial);
 #header("Content-type: application/x-netscape-revocation");
 
-# old Reg Ex doesnt work, new should do the work
-#$regexp = "^R\t.*\t.*\t$serial\t.*\t.*$";
-$regexp = "^R.*$serial.*$";
+$regexp = "^R\t.*\t.*\t$serial\t.*\t.*$";
 $configIndex = $config['index'];
 
 if (exec("egrep '$regexp' '$configIndex'")) {