diff --git a/net/key/af_key.c b/net/key/af_key.c
index c5fbd7589681..9da862070dd8 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1710,6 +1710,7 @@ static int key_notify_sa_flush(const struct km_event *c)
 	hdr->sadb_msg_version = PF_KEY_V2;
 	hdr->sadb_msg_errno = (uint8_t) 0;
 	hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t));
+	hdr->sadb_msg_reserved = 0;
 
 	pfkey_broadcast(skb, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net);
 
@@ -2699,6 +2700,7 @@ static int key_notify_policy_flush(const struct km_event *c)
 	hdr->sadb_msg_errno = (uint8_t) 0;
 	hdr->sadb_msg_satype = SADB_SATYPE_UNSPEC;
 	hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t));
+	hdr->sadb_msg_reserved = 0;
 	pfkey_broadcast(skb_out, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net);
 	return 0;