diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index b48d6b5aae8a8..ef0be325a0c63 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -409,6 +409,10 @@ nf_nat_setup_info(struct nf_conn *ct,
 {
 	struct nf_conntrack_tuple curr_tuple, new_tuple;
 
+	/* Can't setup nat info for confirmed ct. */
+	if (nf_ct_is_confirmed(ct))
+		return NF_ACCEPT;
+
 	NF_CT_ASSERT(maniptype == NF_NAT_MANIP_SRC ||
 		     maniptype == NF_NAT_MANIP_DST);
 	BUG_ON(nf_nat_initialized(ct, maniptype));