diff --git a/spring-cloud-gateway-mvc/src/main/java/org/springframework/cloud/gateway/mvc/config/ProxyExchangeArgumentResolver.java b/spring-cloud-gateway-mvc/src/main/java/org/springframework/cloud/gateway/mvc/config/ProxyExchangeArgumentResolver.java
index 009dc8de..f07987ac 100644
--- a/spring-cloud-gateway-mvc/src/main/java/org/springframework/cloud/gateway/mvc/config/ProxyExchangeArgumentResolver.java
+++ b/spring-cloud-gateway-mvc/src/main/java/org/springframework/cloud/gateway/mvc/config/ProxyExchangeArgumentResolver.java
@@ -58,8 +58,8 @@ public class ProxyExchangeArgumentResolver implements HandlerMethodArgumentResol
 	}
 
 	public void setAutoForwardedHeaders(Set<String> autoForwardedHeaders) {
-		this.autoForwardedHeaders = autoForwardedHeaders.stream().map(String::toLowerCase)
-				.collect(toSet());
+		this.autoForwardedHeaders = autoForwardedHeaders == null ? null
+				: autoForwardedHeaders.stream().map(String::toLowerCase).collect(toSet());
 	}
 
 	public void setSensitive(Set<String> sensitive) {