diff --git a/nimble/host/src/ble_gap.c b/nimble/host/src/ble_gap.c
index b3497eb2c..882984f02 100644
--- a/nimble/host/src/ble_gap.c
+++ b/nimble/host/src/ble_gap.c
@@ -2349,6 +2349,11 @@ ble_gap_rx_peroidic_adv_sync_estab(const struct ble_hci_ev_le_subev_periodic_adv
 
     BLE_HS_DBG_ASSERT(ble_gap_sync.psync);
 
+    if (!ble_gap_sync.psync) {
+        ble_hs_unlock();
+        return;
+    }
+
     if (!ev->status) {
         sync_handle = le16toh(ev->sync_handle);