diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
index c9e40c66404..4903120fffe 100644
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -2015,7 +2015,7 @@ unp_externalize(struct mbuf *control, struct mbuf **controlp, int flags)
 	if (controlp != NULL) /* controlp == NULL => free control messages */
 		*controlp = NULL;
 	while (cm != NULL) {
-		MPASS(clen >= sizeof(*cm) && clen <= cm->cmsg_len);
+		MPASS(clen >= sizeof(*cm) && clen >= cm->cmsg_len);
 
 		data = CMSG_DATA(cm);
 		datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;