diff --git a/ext/standard/fsock.c b/ext/standard/fsock.c
index dd273a4e1d2..6a5c388eeb4 100644
--- a/ext/standard/fsock.c
+++ b/ext/standard/fsock.c
@@ -259,12 +259,13 @@ static void php_fsockopen(INTERNAL_FUNCTION_PARAMETERS, int persistent) {
 		struct sockaddr_in server;
 
 		memset(&server, 0, sizeof(server));
-		if((*args[0])->value.str.val[0] == 'u' &&
-			(*args[0])->value.str.val[1] == 'd' &&
-			(*args[0])->value.str.val[2] == 'p' &&
-			(*args[0])->value.str.val[3] == ':' &&
-			(*args[0])->value.str.val[4] == '/' &&
-			(*args[0])->value.str.val[5] == '/') {
+		if(Z_STRLEN_PP(args[0]) >= 6 &&
+		   (*args[0])->value.str.val[0] == 'u' &&
+		   (*args[0])->value.str.val[1] == 'd' &&
+		   (*args[0])->value.str.val[2] == 'p' &&
+		   (*args[0])->value.str.val[3] == ':' &&
+		   (*args[0])->value.str.val[4] == '/' &&
+		   (*args[0])->value.str.val[5] == '/') {
 			udp = 1;
 		}