diff --git a/core/src/main/java/org/springframework/security/access/expression/method/MethodSecurityEvaluationContext.java b/core/src/main/java/org/springframework/security/access/expression/method/MethodSecurityEvaluationContext.java
index 3688f01c480..862c37c6b85 100644
--- a/core/src/main/java/org/springframework/security/access/expression/method/MethodSecurityEvaluationContext.java
+++ b/core/src/main/java/org/springframework/security/access/expression/method/MethodSecurityEvaluationContext.java
@@ -112,7 +112,10 @@ private void addArgumentsAsVariables() {
 		}
 
 		for (int i = 0; i < args.length; i++) {
-			super.setVariable(paramNames[i], args[i]);
+			String parameterName = paramNames[i];
+			if (parameterName != null) {
+				super.setVariable(parameterName, args[i]);
+			}
 		}
 	}