diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 3fdada4cd0..18bcb8ab48 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -124,6 +124,9 @@ static int ComputeNextBlockAndDepth(const CBlockIndex* tip, const CBlockIndex* b
 
 UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex)
 {
+    // Serialize passed information without accessing chain state of the active chain!
+    AssertLockNotHeld(cs_main); // For performance reasons
+
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
     const CBlockIndex* pnext;
@@ -153,6 +156,9 @@ UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex
 
 UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIndex* blockindex, bool txDetails)
 {
+    // Serialize passed information without accessing chain state of the active chain!
+    AssertLockNotHeld(cs_main); // For performance reasons
+
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
     const CBlockIndex* pnext;
@@ -904,12 +910,17 @@ static UniValue getblockheaders(const JSONRPCRequest& request)
         },
     }.Check(request);
 
-    LOCK(cs_main);
-
     std::string strHash = request.params[0].get_str();
     uint256 hash(uint256S(strHash));
 
-    const CBlockIndex* pblockindex = LookupBlockIndex(hash);
+    const CBlockIndex* pblockindex;
+    const CBlockIndex* tip;
+    {
+        LOCK(cs_main);
+        pblockindex = LookupBlockIndex(hash);
+        tip = ::ChainActive().Tip();
+    }
+
     if (!pblockindex) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
     }
@@ -943,7 +954,7 @@ static UniValue getblockheaders(const JSONRPCRequest& request)
 
     for (; pblockindex; pblockindex = ::ChainActive().Next(pblockindex))
     {
-        arrHeaders.push_back(blockheaderToJSON(::ChainActive().Tip(), pblockindex));
+        arrHeaders.push_back(blockheaderToJSON(tip, pblockindex));
         if (--nCount <= 0)
             break;
     }
@@ -1120,8 +1131,6 @@ static UniValue getblock(const JSONRPCRequest& request)
                 },
     }.Check(request);
 
-    LOCK(cs_main);
-
     std::string strHash = request.params[0].get_str();
     uint256 hash(uint256S(strHash));
 
@@ -1133,12 +1142,20 @@ static UniValue getblock(const JSONRPCRequest& request)
             verbosity = request.params[1].get_bool() ? 1 : 0;
     }
 
-    const CBlockIndex* pblockindex = LookupBlockIndex(hash);
-    if (!pblockindex) {
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
-    }
+    CBlock block;
+    const CBlockIndex* pblockindex;
+    const CBlockIndex* tip;
+    {
+        LOCK(cs_main);
+        pblockindex = LookupBlockIndex(hash);
+        tip = ::ChainActive().Tip();
 
-    const CBlock block = GetBlockChecked(pblockindex);
+        if (!pblockindex) {
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
+        }
+
+        block = GetBlockChecked(pblockindex);
+    }
 
     if (verbosity <= 0)
     {
@@ -1148,7 +1165,7 @@ static UniValue getblock(const JSONRPCRequest& request)
         return strHex;
     }
 
-    return blockToJSON(block, ::ChainActive().Tip(), pblockindex, verbosity >= 2);
+    return blockToJSON(block, tip, pblockindex, verbosity >= 2);
 }
 
 static UniValue pruneblockchain(const JSONRPCRequest& request)
diff --git a/src/rpc/blockchain.h b/src/rpc/blockchain.h
index 6b2d6133d8..6762fed61e 100644
--- a/src/rpc/blockchain.h
+++ b/src/rpc/blockchain.h
@@ -5,9 +5,13 @@
 #ifndef BITCOIN_RPC_BLOCKCHAIN_H
 #define BITCOIN_RPC_BLOCKCHAIN_H
 
-#include <vector>
-#include <stdint.h>
 #include <amount.h>
+#include <sync.h>
+
+#include <stdint.h>
+#include <vector>
+
+extern RecursiveMutex cs_main;
 
 class CBlock;
 class CBlockIndex;
@@ -33,7 +37,7 @@ double GetDifficulty(const CBlockIndex* blockindex);
 void RPCNotifyBlockChange(bool ibd, const CBlockIndex *);
 
 /** Block description to JSON */
-UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIndex* blockindex, bool txDetails = false);
+UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIndex* blockindex, bool txDetails = false) LOCKS_EXCLUDED(cs_main);
 
 /** Mempool information to JSON */
 UniValue MempoolInfoToJSON(const CTxMemPool& pool);
@@ -42,7 +46,7 @@ UniValue MempoolInfoToJSON(const CTxMemPool& pool);
 UniValue MempoolToJSON(const CTxMemPool& pool, bool verbose = false);
 
 /** Block header to JSON */
-UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex);
+UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex) LOCKS_EXCLUDED(cs_main);
 
 /** Used by getblockstats to get feerates at different percentiles by weight  */
 void CalculatePercentilesBySize(CAmount result[NUM_GETBLOCKSTATS_PERCENTILES], std::vector<std::pair<CAmount, int64_t>>& scores, int64_t total_size);