From aa2d52a180129355931c72dfcc3977a4d47bfba5 Mon Sep 17 00:00:00 2001
From: Sushil-19 <dubesushil19007@gmail.com>
Date: Tue, 3 Mar 2026 14:59:09 +0530
Subject: [PATCH 1/2] internal/ethapi: validate explicit transaction type in
 RPC calls

---
 internal/ethapi/transaction_args.go | 46 +++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/internal/ethapi/transaction_args.go b/internal/ethapi/transaction_args.go
index 4fb30e6289..284a2ab308 100644
--- a/internal/ethapi/transaction_args.go
+++ b/internal/ethapi/transaction_args.go
@@ -40,6 +40,8 @@ import (
 // TransactionArgs represents the arguments to construct a new transaction
 // or a message call.
 type TransactionArgs struct {
+	Type                 *hexutil.Uint64 `json:"type,omitempty"`
+
 	From                 *common.Address `json:"from"`
 	To                   *common.Address `json:"to"`
 	Gas                  *hexutil.Uint64 `json:"gas"`
@@ -72,6 +74,24 @@ type TransactionArgs struct {
 	AuthorizationList []types.SetCodeAuthorization `json:"authorizationList"`
 }
 
+func (args *TransactionArgs) inferTxType(defaultType int) int {
+    usedType := types.LegacyTxType
+    switch {
+    case args.AuthorizationList != nil || defaultType == types.SetCodeTxType:
+        usedType = types.SetCodeTxType
+    case args.BlobHashes != nil || defaultType == types.BlobTxType:
+        usedType = types.BlobTxType
+    case args.MaxFeePerGas != nil || defaultType == types.DynamicFeeTxType:
+        usedType = types.DynamicFeeTxType
+    case args.AccessList != nil || defaultType == types.AccessListTxType:
+        usedType = types.AccessListTxType
+    }
+    if args.GasPrice != nil {
+        usedType = types.LegacyTxType
+    }
+    return usedType
+}
+
 // from retrieves the transaction sender address.
 func (args *TransactionArgs) from() common.Address {
 	if args.From == nil {
@@ -176,6 +196,32 @@ func (args *TransactionArgs) setDefaults(ctx context.Context, b Backend, config
 	} else {
 		args.ChainID = (*hexutil.Big)(want)
 	}
+
+	// Validate explicit transaction type if provided
+	if args.Type != nil {
+		requested := int(*args.Type)
+
+		// Validate supported types
+		switch requested {
+		case types.LegacyTxType,
+			types.AccessListTxType,
+			types.DynamicFeeTxType,
+			types.BlobTxType,
+			types.SetCodeTxType:
+			// ok
+		default:
+			return fmt.Errorf("unsupported transaction type: %d", requested)
+		}
+
+		inferred := args.inferTxType(types.LegacyTxType)
+
+		if requested != inferred {
+			return fmt.Errorf(
+				"transaction type mismatch (requested=%d inferred=%d)",
+				requested, inferred,
+			)
+		}
+	}
 	return nil
 }
 

From 0268f2e03df74c1e7db2e76218fb7ac796342d41 Mon Sep 17 00:00:00 2001
From: Sushil-19 <dubesushil19007@gmail.com>
Date: Tue, 3 Mar 2026 15:24:08 +0530
Subject: [PATCH 2/2] internal/ethapi: apply goimports formatting

---
 internal/ethapi/transaction_args.go | 32 ++++++++++++++---------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/internal/ethapi/transaction_args.go b/internal/ethapi/transaction_args.go
index 284a2ab308..ab709d3558 100644
--- a/internal/ethapi/transaction_args.go
+++ b/internal/ethapi/transaction_args.go
@@ -40,7 +40,7 @@ import (
 // TransactionArgs represents the arguments to construct a new transaction
 // or a message call.
 type TransactionArgs struct {
-	Type                 *hexutil.Uint64 `json:"type,omitempty"`
+	Type *hexutil.Uint64 `json:"type,omitempty"`
 
 	From                 *common.Address `json:"from"`
 	To                   *common.Address `json:"to"`
@@ -75,21 +75,21 @@ type TransactionArgs struct {
 }
 
 func (args *TransactionArgs) inferTxType(defaultType int) int {
-    usedType := types.LegacyTxType
-    switch {
-    case args.AuthorizationList != nil || defaultType == types.SetCodeTxType:
-        usedType = types.SetCodeTxType
-    case args.BlobHashes != nil || defaultType == types.BlobTxType:
-        usedType = types.BlobTxType
-    case args.MaxFeePerGas != nil || defaultType == types.DynamicFeeTxType:
-        usedType = types.DynamicFeeTxType
-    case args.AccessList != nil || defaultType == types.AccessListTxType:
-        usedType = types.AccessListTxType
-    }
-    if args.GasPrice != nil {
-        usedType = types.LegacyTxType
-    }
-    return usedType
+	usedType := types.LegacyTxType
+	switch {
+	case args.AuthorizationList != nil || defaultType == types.SetCodeTxType:
+		usedType = types.SetCodeTxType
+	case args.BlobHashes != nil || defaultType == types.BlobTxType:
+		usedType = types.BlobTxType
+	case args.MaxFeePerGas != nil || defaultType == types.DynamicFeeTxType:
+		usedType = types.DynamicFeeTxType
+	case args.AccessList != nil || defaultType == types.AccessListTxType:
+		usedType = types.AccessListTxType
+	}
+	if args.GasPrice != nil {
+		usedType = types.LegacyTxType
+	}
+	return usedType
 }
 
 // from retrieves the transaction sender address.