diff --git a/packages/dev-middleware/src/__tests__/InspectorDebuggerUtils.js b/packages/dev-middleware/src/__tests__/InspectorDebuggerUtils.js
index 172d0270a798a9..d847bce6aa7b7d 100644
--- a/packages/dev-middleware/src/__tests__/InspectorDebuggerUtils.js
+++ b/packages/dev-middleware/src/__tests__/InspectorDebuggerUtils.js
@@ -22,11 +22,17 @@ export class DebuggerAgent {
   #ws: ?WebSocket;
   #readyPromise: Promise<void>;
 
-  constructor(url: string, signal?: AbortSignal, hostHeader?: ?string) {
+  constructor(
+    url: string,
+    signal?: AbortSignal,
+    headers?: ?{[string]: unknown},
+  ) {
     const ws = new WebSocket(url, {
       // The mock server uses a self-signed certificate.
       rejectUnauthorized: false,
-      ...(hostHeader != null ? {headers: {Host: hostHeader}} : {}),
+      ...(headers != null
+        ? {headers}
+        : {headers: {Origin: 'http://localhost:8081'}}),
     });
     this.#ws = ws;
     ws.on('message', data => {
@@ -116,9 +122,9 @@ export class DebuggerMock extends DebuggerAgent {
 export async function createDebuggerMock(
   url: string,
   signal: AbortSignal,
-  hostHeader?: ?string,
+  headers?: ?{[string]: unknown},
 ): Promise<DebuggerMock> {
-  const debuggerMock = new DebuggerMock(url, signal, hostHeader);
+  const debuggerMock = new DebuggerMock(url, signal, headers);
   await debuggerMock.ready();
   return debuggerMock;
 }
diff --git a/packages/dev-middleware/src/__tests__/InspectorProtocolUtils.js b/packages/dev-middleware/src/__tests__/InspectorProtocolUtils.js
index 3d12d534541243..3b7470bbc02f2f 100644
--- a/packages/dev-middleware/src/__tests__/InspectorProtocolUtils.js
+++ b/packages/dev-middleware/src/__tests__/InspectorProtocolUtils.js
@@ -116,11 +116,12 @@ export async function createAndConnectTarget(
   signal: AbortSignal,
   page: PageFromDevice,
   {
-    debuggerHostHeader = null,
+    debuggerHeaders = null,
     deviceId = null,
     deviceHostHeader = null,
   }: Readonly<{
-    debuggerHostHeader?: ?string,
+    debuggerHeaders?: ?{[string]: unknown},
+    debuggerOriginHeader?: ?string,
     deviceId?: ?string,
     deviceHostHeader?: ?string,
   }> = {},
@@ -151,7 +152,7 @@ export async function createAndConnectTarget(
     debugger_ = await createDebuggerMock(
       webSocketDebuggerUrl,
       signal,
-      debuggerHostHeader,
+      debuggerHeaders,
     );
     await until(() => expect(device.connect).toBeCalled());
   } catch (e) {
diff --git a/packages/dev-middleware/src/__tests__/InspectorProxyCdpRewritingHacks-test.js b/packages/dev-middleware/src/__tests__/InspectorProxyCdpRewritingHacks-test.js
index 3b5513f314c332..7be509389c4bcb 100644
--- a/packages/dev-middleware/src/__tests__/InspectorProxyCdpRewritingHacks-test.js
+++ b/packages/dev-middleware/src/__tests__/InspectorProxyCdpRewritingHacks-test.js
@@ -273,7 +273,10 @@ describe.each(['HTTP', 'HTTPS'])(
               vm: 'bar-vm',
             },
             {
-              debuggerHostHeader: 'localhost:' + serverRef.port,
+              debuggerHeaders: {
+                Host: 'localhost:' + serverRef.port,
+                Origin: 'http://localhost:8081',
+              },
               deviceHostHeader: sourceHost,
             },
           );
diff --git a/packages/dev-middleware/src/__tests__/InspectorProxyCdpTransport-test.js b/packages/dev-middleware/src/__tests__/InspectorProxyCdpTransport-test.js
index 7b49a560beb493..39bdf1503f4a10 100644
--- a/packages/dev-middleware/src/__tests__/InspectorProxyCdpTransport-test.js
+++ b/packages/dev-middleware/src/__tests__/InspectorProxyCdpTransport-test.js
@@ -384,5 +384,41 @@ describe.each(['HTTP', 'HTTPS'])(
         debugger2?.close();
       }
     });
+
+    test('debugger connection with invalid origin is rejected', async () => {
+      const device1 = await createDeviceMock(
+        `${serverRef.serverBaseWsUrl}/inspector/device?device=device1&name=foo&app=bar`,
+        autoCleanup.signal,
+      );
+      try {
+        device1.getPages.mockImplementation(() => [
+          {
+            app: 'bar-app',
+            id: 'page1',
+            title: 'bar-title',
+            vm: 'bar-vm',
+          },
+        ]);
+
+        let pageList: JsonPagesListResponse = [];
+        await until(async () => {
+          pageList = (await fetchJson(
+            `${serverRef.serverBaseUrl}/json`,
+            // $FlowFixMe[unclear-type]
+          ): any);
+          expect(pageList).toHaveLength(1);
+        });
+        const [{webSocketDebuggerUrl}] = pageList;
+        expect(webSocketDebuggerUrl).toBeDefined();
+
+        await expect(
+          createDebuggerMock(webSocketDebuggerUrl, autoCleanup.signal, {
+            Origin: 'null',
+          }),
+        ).rejects.toThrow('Unexpected server response: 401');
+      } finally {
+        device1.close();
+      }
+    });
   },
 );
diff --git a/packages/dev-middleware/src/inspector-proxy/InspectorProxy.js b/packages/dev-middleware/src/inspector-proxy/InspectorProxy.js
index 19862b95d87f47..ea887884d31966 100644
--- a/packages/dev-middleware/src/inspector-proxy/InspectorProxy.js
+++ b/packages/dev-middleware/src/inspector-proxy/InspectorProxy.js
@@ -32,6 +32,11 @@ import WS from 'ws';
 
 const debug = require('debug')('Metro:InspectorProxy');
 
+const WS_DEBUGGER_ALLOWED_ORIGINS = new Set([
+  'http://localhost:8081',
+  'http://127.0.0.1:8081',
+]);
+
 const WS_DEVICE_URL = '/inspector/device';
 const WS_DEBUGGER_URL = '/inspector/debug';
 const PAGES_LIST_JSON_URL = '/json';
@@ -484,7 +489,17 @@ export default class InspectorProxy implements InspectorProxyQueries {
       // Don't crash on exceptionally large messages - assume the debugger is
       // well-behaved and the device is prepared to handle large messages.
       maxPayload: 0,
+      // Verify the client is from an allowed origin.
+      // $FlowFixMe[incompatible-type] - `ws` definition is incomplete.
+      verifyClient: (
+        info: Readonly<{
+          origin: string,
+          secure: boolean,
+          req: http$IncomingMessage<>,
+        }>,
+      ) => WS_DEBUGGER_ALLOWED_ORIGINS.has(info.origin),
     });
+
     // $FlowFixMe[value-as-type]
     wss.on('connection', async (socket: WS, req) => {
       const wssTimestamp = Date.now();