diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index 886d8c53c4fc..a40f067325b1 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -1082,7 +1082,7 @@ rtsock_msg_buffer(int type, struct rt_addrinfo *rtinfo, struct walkarg *w, int *
 {
 	int i;
 	int len, buflen = 0, dlen;
-	caddr_t cp;
+	caddr_t cp = NULL;
 	struct rt_msghdr *rtm = NULL;
 #ifdef INET6
 	struct sockaddr_storage ss;