diff --git a/app/scripts/lib/tx-verification/tx-verification-middleware.ts b/app/scripts/lib/tx-verification/tx-verification-middleware.ts
index 46bbce9468b3..34e6b18e7074 100644
--- a/app/scripts/lib/tx-verification/tx-verification-middleware.ts
+++ b/app/scripts/lib/tx-verification/tx-verification-middleware.ts
@@ -1,54 +1,104 @@
 import { hashMessage } from '@ethersproject/hash';
 import { verifyMessage } from '@ethersproject/wallet';
+import type { NetworkController } from '@metamask/network-controller';
+import { rpcErrors } from '@metamask/rpc-errors';
+import { Json, JsonRpcParams, hasProperty, isObject } from '@metamask/utils';
 import {
-  Json,
-  JsonRpcParams,
   JsonRpcRequest,
   JsonRpcResponse,
-} from '@metamask/utils';
-import {
   JsonRpcEngineEndCallback,
   JsonRpcEngineNextCallback,
 } from 'json-rpc-engine';
 import { SIG_LEN, TRUSTED_BRIDGE_SIGNER } from '../../../../shared/constants/bridge';
 import { FIRST_PARTY_CONTRACT_NAMES } from '../../../../shared/constants/first-party-contracts';
 
-export function txVerificationMiddleware(
-  req: JsonRpcRequest<JsonRpcParams>,
-  _res: JsonRpcResponse<Json>,
-  next: JsonRpcEngineNextCallback,
-  end: JsonRpcEngineEndCallback,
+type TxParams = {
+  chainId?: `0x${string}`;
+  data: string;
+  from: string;
+  to: string;
+  value: string;
+};
+
+/**
+ * Creates a middleware function that verifies bridge transactions from the
+ * Portfolio.
+ *
+ * @param networkController - The network controller instance.
+ * @returns The middleware function.
+ */
+export function createTxVerificationMiddleware(
+  networkController: NetworkController,
 ) {
-  // ignore if not sendTransaction and if the params not an array
-  if (req.method !== 'eth_sendTransaction' || !Array.isArray(req.params)) {
+  return function txVerificationMiddleware(
+    req: JsonRpcRequest<JsonRpcParams>,
+    _res: JsonRpcResponse<Json>,
+    next: JsonRpcEngineNextCallback,
+    end: JsonRpcEngineEndCallback,
+  ) {
+    if (
+      req.method !== 'eth_sendTransaction' ||
+      !Array.isArray(req.params) ||
+      !isValidParams(req.params)
+    ) {
+      return next();
+    }
+
+    // the tx object is the first element
+    const params = req.params[0];
+
+    const chainId =
+      typeof params.chainId === 'string'
+        ? (params.chainId.toLowerCase() as `0x${string}`)
+        : networkController.state.providerConfig.chainId;
+
+    // if the recipient address is not the bridge contract, skip verification
+    if (
+      params.to.toLowerCase() !==
+      FIRST_PARTY_CONTRACT_NAMES['MetaMask Bridge'][chainId].toLowerCase()
+    ) {
+      return next();
+    }
+
+    const paramsToVerify = {
+      to: hashMessage(params.to.toLowerCase()),
+      from: hashMessage(params.from.toLowerCase()),
+      data: hashMessage(
+        params.data.toLowerCase().substring(0, params.data.length - SIG_LEN),
+      ),
+      value: hashMessage(params.value.toLowerCase()),
+    };
+    const h = hashMessage(JSON.stringify(paramsToVerify));
+
+    // signature is 130 chars in length at the end
+    const signature = `0x${params.data.substring(-SIG_LEN)}`;
+    const addressToVerify = verifyMessage(h, signature);
+
+    if (addressToVerify.toLowerCase() !== TRUSTED_BRIDGE_SIGNER.toLowerCase()) {
+      return end(
+        rpcErrors.invalidParams('Invalid bridge transaction signature.'),
+      );
+    }
     return next();
-  }
-
-  // 0 tx object is the first element
-  const params = req.params[0];
-  const paramsToVerify = {
-    to: hashMessage(params.to.toLowerCase()),
-    from: hashMessage(params.from.toLowerCase()),
-    data: hashMessage(
-      // strip signature from data
-      params.data.toLowerCase().substr(0, params.data.length - SIG_LEN),
-    ),
-    value: hashMessage(params.value.toLowerCase()),
   };
-  const h = hashMessage(JSON.stringify(paramsToVerify));
-  // signature is 130 chars in length at the end
-  const signature = `0x${params.data.substr(-SIG_LEN)}`;
-  const addressToVerify = verifyMessage(h, signature);
-  const canSubmit =
-    params.to.toLowerCase() ===
-    FIRST_PARTY_CONTRACT_NAMES['MetaMask Bridge'][params.chainId].toLowerCase()
-      ? addressToVerify.toLowerCase() === TRUSTED_BRIDGE_SIGNER.toLowerCase()
-      : true;
-
-  if (!canSubmit) {
-    end(new Error('Validation Error'));
-  }
-
-  // successful validation
-  return next();
+}
+
+/**
+ * Checks if the params of a JSON-RPC request are valid `eth_sendTransaction`
+ * params.
+ *
+ * @param params - The params to validate.
+ * @returns Whether the params are valid.
+ */
+function isValidParams(params: Json[]): params is [TxParams] {
+  return (
+    isObject(params[0]) &&
+    (!hasProperty(params[0], 'chainId') ||
+      (typeof params[0].chainId === 'string' &&
+        params[0].chainId.startsWith('0x'))) &&
+    typeof params[0].data === 'string' &&
+    typeof params[0].from === 'string' &&
+    typeof params[0].to === 'string' &&
+    typeof params[0].value === 'string'
+  );
 }
diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index c3d1b6374d67..b2f8d0d99ed9 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -219,6 +219,7 @@ import {
   getSmartTransactionsOptInStatus,
   getCurrentChainSupportsSmartTransactions,
 } from '../../shared/modules/selectors';
+import { BaseUrl } from '../../shared/constants/urls';
 import {
   ///: BEGIN:ONLY_INCLUDE_IF(build-mmi)
   handleMMITransactionUpdate,
@@ -329,7 +330,7 @@ import AuthenticationController from './controllers/authentication/authenticatio
 import UserStorageController from './controllers/user-storage/user-storage-controller';
 import { PushPlatformNotificationsController } from './controllers/push-platform-notifications/push-platform-notifications';
 import { MetamaskNotificationsController } from './controllers/metamask-notifications/metamask-notifications';
-import { txVerificationMiddleware } from './lib/tx-verification/tx-verification-middleware';
+import { createTxVerificationMiddleware } from './lib/tx-verification/tx-verification-middleware';
 import { updateSecurityAlertResponse } from './lib/ppom/ppom-util';
 
 export const METAMASK_CONTROLLER_EVENTS = {
@@ -5119,8 +5120,8 @@ export default class MetamaskController extends EventEmitter {
     engine.push(createLoggerMiddleware({ origin }));
     engine.push(this.permissionLogController.createMiddleware());
 
-    if (origin === 'https://portfolio.metamask.io' || 'http://localhost:3000') {
-      engine.push(txVerificationMiddleware);
+    if (origin === BaseUrl.Portfolio) {
+      engine.push(createTxVerificationMiddleware(this.networkController));
     }
 
     ///: BEGIN:ONLY_INCLUDE_IF(blockaid)
diff --git a/package.json b/package.json
index e11a4150359a..9f375e59f055 100644
--- a/package.json
+++ b/package.json
@@ -328,6 +328,7 @@
     "@metamask/providers": "^14.0.2",
     "@metamask/queued-request-controller": "^0.10.0",
     "@metamask/rate-limit-controller": "^5.0.1",
+    "@metamask/rpc-errors": "^6.2.1",
     "@metamask/safe-event-emitter": "^3.1.1",
     "@metamask/scure-bip39": "^2.0.3",
     "@metamask/selected-network-controller": "^13.0.0",
diff --git a/yarn.lock b/yarn.lock
index 164c81e21b4a..1bf391473ce0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -24927,6 +24927,7 @@ __metadata:
     "@metamask/providers": "npm:^14.0.2"
     "@metamask/queued-request-controller": "npm:^0.10.0"
     "@metamask/rate-limit-controller": "npm:^5.0.1"
+    "@metamask/rpc-errors": "npm:^6.2.1"
     "@metamask/safe-event-emitter": "npm:^3.1.1"
     "@metamask/scure-bip39": "npm:^2.0.3"
     "@metamask/selected-network-controller": "npm:^13.0.0"