diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index b8cc3339a249..aed967e2f30f 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -1158,6 +1158,16 @@ int nf_conntrack_tcp_packet(struct nf_conn *ct,
 			nf_ct_kill_acct(ct, ctinfo, skb);
 			return NF_ACCEPT;
 		}
+
+		if (index == TCP_SYN_SET && old_state == TCP_CONNTRACK_SYN_SENT) {
+			/* do not renew timeout on SYN retransmit.
+			 *
+			 * Else port reuse by client or NAT middlebox can keep
+			 * entry alive indefinitely (including nat info).
+			 */
+			return NF_ACCEPT;
+		}
+
 		/* ESTABLISHED without SEEN_REPLY, i.e. mid-connection
 		 * pickup with loose=1. Avoid large ESTABLISHED timeout.
 		 */