diff --git a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/graphql/internal/Scalars.java b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/graphql/internal/Scalars.java
index 4b646b9f55..4a98d9a49a 100644
--- a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/graphql/internal/Scalars.java
+++ b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/graphql/internal/Scalars.java
@@ -14,6 +14,7 @@
  */
 package org.hyperledger.besu.ethereum.api.graphql.internal;
 
+import org.hyperledger.besu.ethereum.api.jsonrpc.internal.results.Quantity;
 import org.hyperledger.besu.ethereum.core.Address;
 import org.hyperledger.besu.ethereum.core.Hash;
 
@@ -55,8 +56,13 @@ public class Scalars {
           if (!(input instanceof StringValue)) {
             throw new CoercingParseLiteralException("Value is not any Address : '" + input + "'");
           }
+          String inputValue = ((StringValue) input).getValue();
+          if (!Quantity.isValid(inputValue)) {
+            throw new CoercingParseLiteralException(
+                "Address value '" + inputValue + "' is not prefixed with 0x");
+          }
           try {
-            return Address.fromHexStringStrict(((StringValue) input).getValue());
+            return Address.fromHexStringStrict(inputValue);
           } catch (final IllegalArgumentException e) {
             throw new CoercingParseLiteralException("Value is not any Address : '" + input + "'");
           }
@@ -121,8 +127,13 @@ public class Scalars {
           if (!(input instanceof StringValue)) {
             throw new CoercingParseLiteralException("Value is not any Bytes : '" + input + "'");
           }
+          String inputValue = ((StringValue) input).getValue();
+          if (!Quantity.isValid(inputValue)) {
+            throw new CoercingParseLiteralException(
+                "Bytes value '" + inputValue + "' is not prefixed with 0x");
+          }
           try {
-            return Bytes.fromHexStringLenient(((StringValue) input).getValue());
+            return Bytes.fromHexStringLenient(inputValue);
           } catch (final IllegalArgumentException e) {
             throw new CoercingParseLiteralException("Value is not any Bytes : '" + input + "'");
           }
@@ -156,8 +167,13 @@ public class Scalars {
           if (!(input instanceof StringValue)) {
             throw new CoercingParseLiteralException("Value is not any Bytes32 : '" + input + "'");
           }
+          String inputValue = ((StringValue) input).getValue();
+          if (!Quantity.isValid(inputValue)) {
+            throw new CoercingParseLiteralException(
+                "Bytes32 value '" + inputValue + "' is not prefixed with 0x");
+          }
           try {
-            return Bytes32.fromHexStringLenient(((StringValue) input).getValue());
+            return Bytes32.fromHexStringLenient(inputValue);
           } catch (final IllegalArgumentException e) {
             throw new CoercingParseLiteralException("Value is not any Bytes32 : '" + input + "'");
           }
diff --git a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/Quantity.java b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/Quantity.java
index 21ee63ed67..f2e7617813 100644
--- a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/Quantity.java
+++ b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/Quantity.java
@@ -77,6 +77,16 @@ public class Quantity {
     return String.format("%s%s%s", HEX_PREFIX, zeroPadding, formatted);
   }
 
+  /**
+   * Checks if value is prefixed with '0x'
+   *
+   * @param value that is checked
+   * @return true if value is prefixed with '0x', false otherwise
+   */
+  public static boolean isValid(final String value) {
+    return value.startsWith(HEX_PREFIX);
+  }
+
   private static String uint256ToHex(final UInt256Value<?> value) {
     return value == null ? null : formatMinimalValue(value.toMinimalBytes().toShortHexString());
   }
diff --git a/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/graphql/EthGraphQLHttpBySpecTest.java b/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/graphql/EthGraphQLHttpBySpecTest.java
index 4f4f9088e0..04bcd51206 100644
--- a/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/graphql/EthGraphQLHttpBySpecTest.java
+++ b/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/graphql/EthGraphQLHttpBySpecTest.java
@@ -47,6 +47,7 @@ public class EthGraphQLHttpBySpecTest extends AbstractEthGraphQLHttpServiceTest
     specs.add("eth_blockNumber");
 
     specs.add("eth_call_Block8");
+    specs.add("eth_call_Block8_invalidHexBytesData");
     specs.add("eth_call_BlockLatest");
 
     specs.add("eth_estimateGas_transfer");
@@ -58,11 +59,13 @@ public class EthGraphQLHttpBySpecTest extends AbstractEthGraphQLHttpServiceTest
     specs.add("eth_getBalance_0x19");
     specs.add("eth_getBalance_invalidAccountBlockNumber");
     specs.add("eth_getBalance_invalidAccountLatest");
+    specs.add("eth_getBalance_invalidHexAddress");
     specs.add("eth_getBalance_latest");
     specs.add("eth_getBalance_toobig_bn");
     specs.add("eth_getBalance_without_addr");
 
     specs.add("eth_getBlock_byHash");
+    specs.add("eth_getBlock_byHash_InvalidHexBytes32Hash");
     specs.add("eth_getBlock_byHashInvalid");
     specs.add("eth_getBlock_byNumber");
     specs.add("eth_getBlock_byNumberInvalid");
diff --git a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_Block8.json b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_Block8.json
index c2d0014b30..26a2eb4a45 100644
--- a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_Block8.json
+++ b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_Block8.json
@@ -1,5 +1,5 @@
 {
-  "request": "{block(number :\"0x8\") {number call (data : {from : \"a94f5374fce5edbc8e2a8697c15331677e6ebf0b\", to: \"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\", data :\"0x12a7b914\"}){data status}}}"
+  "request": "{block(number :\"0x8\") {number call (data : {from : \"0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b\", to: \"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\", data :\"0x12a7b914\"}){data status}}}"
   ,
   "response":{
     "data" : {
diff --git a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_Block8_invalidHexBytesData.json b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_Block8_invalidHexBytesData.json
new file mode 100644
index 0000000000..2d876b4270
--- /dev/null
+++ b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_Block8_invalidHexBytesData.json
@@ -0,0 +1,21 @@
+{
+  "request": "{block(number :\"0x8\") {number call (data : {from : \"0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b\", to: \"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\", data :\"12a7b914\"}){data status}}}"
+  ,
+  "response": {
+    "errors": [
+      {
+        "message": "Validation error of type WrongType: argument 'data.data' with value 'StringValue{value='12a7b914'}' is not a valid 'Bytes' - Bytes value '12a7b914' is not prefixed with 0x @ 'block/call'",
+        "locations": [
+          {
+            "line": 1,
+            "column": 37
+          }
+        ],
+        "extensions": {
+          "classification": "ValidationError"
+        }
+      }
+    ]
+  },
+  "statusCode": 400
+}
\ No newline at end of file
diff --git a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_BlockLatest.json b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_BlockLatest.json
index 129811c38f..7478c29a74 100644
--- a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_BlockLatest.json
+++ b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_call_BlockLatest.json
@@ -1,5 +1,5 @@
 {
-  "request": "{block {number call (data : {from : \"a94f5374fce5edbc8e2a8697c15331677e6ebf0b\", to: \"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\", data :\"0x12a7b914\"}){data status}}}"
+  "request": "{block {number call (data : {from : \"0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b\", to: \"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\", data :\"0x12a7b914\"}){data status}}}"
   ,
   "response":{
     "data" : {
diff --git a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_getBalance_invalidHexAddress.json b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_getBalance_invalidHexAddress.json
new file mode 100644
index 0000000000..ba027020c7
--- /dev/null
+++ b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_getBalance_invalidHexAddress.json
@@ -0,0 +1,20 @@
+{
+  "request": "{account(blockNumber:\"0x19\", address: \"6295ee1b4f6dd65047762f924ecd367c17eabf8f\") { balance } }",
+  "response": {
+    "errors": [
+      {
+        "message": "Validation error of type WrongType: argument 'address' with value 'StringValue{value='6295ee1b4f6dd65047762f924ecd367c17eabf8f'}' is not a valid 'Address' - Address value '6295ee1b4f6dd65047762f924ecd367c17eabf8f' is not prefixed with 0x @ 'account'",
+        "locations": [
+          {
+            "line": 1,
+            "column": 30
+          }
+        ],
+        "extensions": {
+          "classification": "ValidationError"
+        }
+      }
+    ]
+  },
+  "statusCode": 400
+}
diff --git a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_getBlock_byHash_InvalidHexBytes32Hash.json b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_getBlock_byHash_InvalidHexBytes32Hash.json
new file mode 100644
index 0000000000..792775e910
--- /dev/null
+++ b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/eth_getBlock_byHash_InvalidHexBytes32Hash.json
@@ -0,0 +1,20 @@
+{
+  "request": "{block (hash : \"c8df1f061abb4d0c107b2b1a794ade8780b3120e681f723fe55a7be586d95ba6\") {number } }",
+  "response": {
+    "errors": [
+      {
+        "message": "Validation error of type WrongType: argument 'hash' with value 'StringValue{value='c8df1f061abb4d0c107b2b1a794ade8780b3120e681f723fe55a7be586d95ba6'}' is not a valid 'Bytes32' - Bytes32 value 'c8df1f061abb4d0c107b2b1a794ade8780b3120e681f723fe55a7be586d95ba6' is not prefixed with 0x @ 'block'",
+        "locations": [
+          {
+            "line": 1,
+            "column": 9
+          }
+        ],
+        "extensions": {
+          "classification": "ValidationError"
+        }
+      }
+    ]
+  },
+  "statusCode": 400
+}
\ No newline at end of file
diff --git a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/graphql_pending.json b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/graphql_pending.json
index 0acb42b455..46cad8c1c7 100644
--- a/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/graphql_pending.json
+++ b/ethereum/api/src/test/resources/org/hyperledger/besu/ethereum/api/graphql/graphql_pending.json
@@ -1,6 +1,6 @@
 {
   "request":
-    "{ pending { transactionCount transactions { nonce gas } account(address:\"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\") { balance} estimateGas(data:{}) call (data : {from : \"a94f5374fce5edbc8e2a8697c15331677e6ebf0b\", to: \"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\", data :\"0x12a7b914\"}){data status}} }",
+    "{ pending { transactionCount transactions { nonce gas } account(address:\"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\") { balance} estimateGas(data:{}) call (data : {from : \"0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b\", to: \"0x6295ee1b4f6dd65047762f924ecd367c17eabf8f\", data :\"0x12a7b914\"}){data status}} }",
 
   "response": {
     "data": {