diff --git a/src/coinjoin/client.cpp b/src/coinjoin/client.cpp
index bde331a453a1..25c776f5d932 100644
--- a/src/coinjoin/client.cpp
+++ b/src/coinjoin/client.cpp
@@ -558,6 +558,7 @@ bool CCoinJoinClientSession::SignFinalTransaction(const CTransaction& finalTrans
     if (fMasternodeMode || pnode == nullptr) return false;
     if (!mixingMasternode) return false;
 
+    LOCK2(mempool.cs, mixingWallet.cs_wallet);
     LOCK(cs_coinjoin);
 
     finalMutableTransaction = CMutableTransaction{finalTransactionNew};