diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -895,7 +895,8 @@
         return *m_chain;
     }
 
-    const CWalletTx *GetWalletTx(const TxId &txid) const;
+    const CWalletTx *GetWalletTx(const TxId &txid) const
+        EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     //! check whether we are allowed to upgrade (or already support) to the
     //! named feature
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -317,7 +317,7 @@
 }
 
 const CWalletTx *CWallet::GetWalletTx(const TxId &txid) const {
-    LOCK(cs_wallet);
+    AssertLockHeld(cs_wallet);
     std::map<TxId, CWalletTx>::const_iterator it = mapWallet.find(txid);
     if (it == mapWallet.end()) {
         return nullptr;
@@ -2201,6 +2201,7 @@
     }
 
     // Trusted if all inputs are from us and are in the mempool:
+    LOCK(pwallet->cs_wallet);
     for (const CTxIn &txin : tx->vin) {
         // Transactions not sent by us: not trusted
         const CWalletTx *parent = pwallet->GetWalletTx(txin.prevout.GetTxId());