diff --git a/src/xrpld/app/ledger/detail/InboundLedger.cpp b/src/xrpld/app/ledger/detail/InboundLedger.cpp
index ba01dce17d..826d9559f4 100644
--- a/src/xrpld/app/ledger/detail/InboundLedger.cpp
+++ b/src/xrpld/app/ledger/detail/InboundLedger.cpp
@@ -434,6 +434,8 @@ InboundLedger::pmDowncast()
 void
 InboundLedger::done()
 {
+    ScopedLockType const sl(mtx_);
+
     if (mSignaled)
         return;