diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index e8e7f108b016..82e42d8e2ea0 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4202,6 +4202,21 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
 
 	switch (ev->status) {
 	case 0x00:
+		/* The synchronous connection complete event should only be
+		 * sent once per new connection. Receiving a successful
+		 * complete event when the connection status is already
+		 * BT_CONNECTED means that the device is misbehaving and sent
+		 * multiple complete event packets for the same new connection.
+		 *
+		 * Registering the device more than once can corrupt kernel
+		 * memory, hence upon detecting this invalid event, we report
+		 * an error and ignore the packet.
+		 */
+		if (conn->state == BT_CONNECTED) {
+			bt_dev_err(hdev, "Ignoring connect complete event for existing connection");
+			goto unlock;
+		}
+
 		conn->handle = __le16_to_cpu(ev->handle);
 		conn->state  = BT_CONNECTED;
 		conn->type   = ev->link_type;