diff --git a/sys/netinet/in_pcb.c b/sys/netinet/in_pcb.c
--- a/sys/netinet/in_pcb.c
+++ b/sys/netinet/in_pcb.c
@@ -2242,6 +2242,10 @@
 
 	KASSERT((lookupflags & ~(INPLOOKUP_WILDCARD)) == 0,
 	    ("%s: invalid lookup flags %d", __func__, lookupflags));
+	KASSERT(faddr.s_addr != INADDR_ANY,
+	    ("%s: invalid foreign address", __func__));
+	KASSERT(laddr.s_addr != INADDR_ANY,
+	    ("%s: invalid local address", __func__));
 	INP_HASH_LOCK_ASSERT(pcbinfo);
 
 	/*
diff --git a/sys/netinet6/in6_pcb.c b/sys/netinet6/in6_pcb.c
--- a/sys/netinet6/in6_pcb.c
+++ b/sys/netinet6/in6_pcb.c
@@ -980,6 +980,10 @@
 
 	KASSERT((lookupflags & ~(INPLOOKUP_WILDCARD)) == 0,
 	    ("%s: invalid lookup flags %d", __func__, lookupflags));
+	KASSERT(!IN6_IS_ADDR_UNSPECIFIED(faddr),
+	    ("%s: invalid foreign address", __func__));
+	KASSERT(!IN6_IS_ADDR_UNSPECIFIED(laddr),
+	    ("%s: invalid local address", __func__));
 
 	INP_HASH_LOCK_ASSERT(pcbinfo);