diff --git a/packages/playwright-core/src/server/trace/viewer/traceViewer.ts b/packages/playwright-core/src/server/trace/viewer/traceViewer.ts
index f852f6c996..55cbca1cad 100644
--- a/packages/playwright-core/src/server/trace/viewer/traceViewer.ts
+++ b/packages/playwright-core/src/server/trace/viewer/traceViewer.ts
@@ -67,6 +67,10 @@ export async function startTraceViewerServer(options?: TraceViewerServerOptions)
   server.routePrefix('/trace', (request, response) => {
     const url = new URL('http://localhost' + request.url!);
     const relativePath = url.pathname.slice('/trace'.length);
+    if (process.env.PW_HMR) {
+      // When running in Vite HMR mode, port is hardcoded in build.js
+      response.appendHeader('Access-Control-Allow-Origin', 'http://localhost:44223');
+    }
     if (relativePath.endsWith('/stall.js'))
       return true;
     if (relativePath.startsWith('/file')) {