diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -326,6 +326,7 @@
 		 * Preserve compatibility with old programs.
 		 */
 		if (nam->sa_family != AF_UNSPEC ||
+		    nam->sa_len < offsetof(struct sockaddr_in, sin_zero) ||
 		    sinp->sin_addr.s_addr != INADDR_ANY)
 			return (EAFNOSUPPORT);
 		nam->sa_family = AF_INET;
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -1635,6 +1635,7 @@
 		 * Preserve compatibility with old programs.
 		 */
 		if (nam->sa_family != AF_UNSPEC ||
+		    nam->sa_len < offsetof(struct sockaddr_in, sin_zero) ||
 		    sinp->sin_addr.s_addr != INADDR_ANY)
 			return (EAFNOSUPPORT);
 		nam->sa_family = AF_INET;