diff --git a/src/Condition.php b/src/Condition.php
index d243942..021222f 100644
--- a/src/Condition.php
+++ b/src/Condition.php
@@ -192,7 +192,7 @@ private static function evalOperatorCondition(string $operator, $attributeValue,
             case '$gte':
                 return $attributeValue >= $conditionValue;
             case '$regex':
-                return @preg_match('/'.$conditionValue.'/', $attributeValue) === 1;
+                return preg_match('/'.$conditionValue.'/', $attributeValue ?? '') === 1;
             case '$in':
                 if (!is_array($conditionValue)) {
                     return false;