diff --git a/src/core_read.cpp b/src/core_read.cpp
--- a/src/core_read.cpp
+++ b/src/core_read.cpp
@@ -179,6 +179,29 @@
     return result;
 }
 
+// Check that all of the input and output scripts of a transaction contains
+// valid opcodes
+bool CheckTxScriptsSanity(const CMutableTransaction &tx) {
+    // Check input scripts for non-coinbase txs
+    if (!CTransaction(tx).IsCoinBase()) {
+        for (const auto &i : tx.vin) {
+            if (!i.scriptSig.HasValidOps() ||
+                i.scriptSig.size() > MAX_SCRIPT_SIZE) {
+                return false;
+            }
+        }
+    }
+    // Check output scripts
+    for (const auto &o : tx.vout) {
+        if (!o.scriptPubKey.HasValidOps() ||
+            o.scriptPubKey.size() > MAX_SCRIPT_SIZE) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 bool DecodeHexTx(CMutableTransaction &tx, const std::string &strHexTx) {
     if (!IsHex(strHexTx)) {
         return false;
@@ -189,14 +212,14 @@
     CDataStream ssData(txData, SER_NETWORK, PROTOCOL_VERSION);
     try {
         ssData >> tx;
-        if (!ssData.empty()) {
-            return false;
+        if (ssData.eof() && CheckTxScriptsSanity(tx)) {
+            return true;
         }
-    } catch (const std::exception &) {
-        return false;
+    } catch (const std::exception &e) {
+        // Fall through.
     }
 
-    return true;
+    return false;
 }
 
 bool DecodeHexBlockHeader(CBlockHeader &header, const std::string &hex_header) {
diff --git a/src/script/script.h b/src/script/script.h
--- a/src/script/script.h
+++ b/src/script/script.h
@@ -192,6 +192,9 @@
     OP_INVALIDOPCODE = 0xff,
 };
 
+// Maximum value that an opcode can be
+static const unsigned int MAX_OPCODE = FIRST_UNDEFINED_OP_VALUE - 1;
+
 const char *GetOpName(opcodetype opcode);
 
 /**
@@ -566,6 +569,9 @@
     bool IsPushOnly(const_iterator pc) const;
     bool IsPushOnly() const;
 
+    /** Check if the script contains valid OP_CODES */
+    bool HasValidOps() const;
+
     /**
      * Returns whether the script is guaranteed to fail at execution, regardless
      * of the initial stack. This allows outputs to be pruned instantly when
diff --git a/src/script/script.cpp b/src/script/script.cpp
--- a/src/script/script.cpp
+++ b/src/script/script.cpp
@@ -562,3 +562,16 @@
     opcodeRet = static_cast<opcodetype>(opcode);
     return true;
 }
+
+bool CScript::HasValidOps() const {
+    CScript::const_iterator it = begin();
+    while (it < end()) {
+        opcodetype opcode;
+        std::vector<uint8_t> item;
+        if (!GetOp(it, opcode, item) || opcode > MAX_OPCODE ||
+            item.size() > MAX_SCRIPT_ELEMENT_SIZE) {
+            return false;
+        }
+    }
+    return true;
+}
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -3026,6 +3026,34 @@
     }
 }
 
+BOOST_AUTO_TEST_CASE(script_HasValidOps) {
+    // Exercise the HasValidOps functionality
+    CScript script;
+    // Normal script
+    script =
+        ScriptFromHex("76a9141234567890abcdefa1a2a3a4a5a6a7a8a9a0aaab88ac");
+    BOOST_CHECK(script.HasValidOps());
+    script =
+        ScriptFromHex("76a914ff34567890abcdefa1a2a3a4a5a6a7a8a9a0aaab88ac");
+    BOOST_CHECK(script.HasValidOps());
+    // Script with OP_INVALIDOPCODE explicit
+    script = ScriptFromHex("ff88ac");
+    BOOST_CHECK(!script.HasValidOps());
+    // Script with undefined opcode
+    script = ScriptFromHex("88acc0");
+    BOOST_CHECK(!script.HasValidOps());
+
+    // Check all non push opcodes.
+    for (uint8_t opcode = OP_1NEGATE; opcode < FIRST_UNDEFINED_OP_VALUE;
+         opcode++) {
+        script = CScript() << opcode;
+        BOOST_CHECK(script.HasValidOps());
+    }
+
+    script = CScript() << FIRST_UNDEFINED_OP_VALUE;
+    BOOST_CHECK(!script.HasValidOps());
+}
+
 BOOST_AUTO_TEST_CASE(script_can_append_self) {
     CScript s, d;
 
diff --git a/test/functional/test_framework/blocktools.py b/test/functional/test_framework/blocktools.py
--- a/test/functional/test_framework/blocktools.py
+++ b/test/functional/test_framework/blocktools.py
@@ -10,7 +10,6 @@
     OP_DUP,
     OP_EQUALVERIFY,
     OP_HASH160,
-    OP_PUSHDATA2,
     OP_RETURN,
     OP_TRUE,
 )
@@ -178,7 +177,7 @@
 def send_big_transactions(node, utxos, num, fee_multiplier):
     from .cashaddr import decode
     txids = []
-    padding = "1"*(512*127)
+    padding = "1"*512
     addrHash = decode(node.getnewaddress())[2]
 
     for _ in range(num):
@@ -186,13 +185,14 @@
         utxo = utxos.pop()
         txid = int(utxo['txid'], 16)
         ctx.vin.append(CTxIn(COutPoint(txid, int(utxo["vout"])), b""))
-        ctx.vout.append(CTxOut(0, CScript(
-            [OP_RETURN, OP_PUSHDATA2, len(padding), bytes(padding, 'utf-8')])))
         ctx.vout.append(
             CTxOut(int(satoshi_round(utxo['amount']*COIN)),
                    CScript([OP_DUP, OP_HASH160, addrHash, OP_EQUALVERIFY, OP_CHECKSIG])))
+        for i in range(0, 127):
+            ctx.vout.append(CTxOut(0, CScript(
+                [OP_RETURN, bytes(padding, 'utf-8')])))
         # Create a proper fee for the transaction to be mined
-        ctx.vout[1].nValue -= int(fee_multiplier * node.calculate_fee(ctx))
+        ctx.vout[0].nValue -= int(fee_multiplier * node.calculate_fee(ctx))
         signresult = node.signrawtransactionwithwallet(
             ToHex(ctx), None, "NONE|FORKID")
         txid = node.sendrawtransaction(signresult["hex"], True)