diff --git a/engine/src/flutter/lib/web_ui/dev/test_platform.dart b/engine/src/flutter/lib/web_ui/dev/test_platform.dart
index aa6d53c5959..078b18ee863 100644
--- a/engine/src/flutter/lib/web_ui/dev/test_platform.dart
+++ b/engine/src/flutter/lib/web_ui/dev/test_platform.dart
@@ -485,7 +485,7 @@ class BrowserPlatform extends PlatformPlugin {
         request.url.path,
       ));
 
-      if (!fileInDirectory.existsSync()) {
+      if (request.url.path.contains('//') || !fileInDirectory.existsSync()) {
         return shelf.Response.notFound('File not found: ${request.url.path}');
       }
 
diff --git a/engine/src/flutter/lib/web_ui/flutter_js/src/canvaskit_loader.js b/engine/src/flutter/lib/web_ui/flutter_js/src/canvaskit_loader.js
index cf88c3c7ea5..39a696a6a86 100644
--- a/engine/src/flutter/lib/web_ui/flutter_js/src/canvaskit_loader.js
+++ b/engine/src/flutter/lib/web_ui/flutter_js/src/canvaskit_loader.js
@@ -17,7 +17,7 @@ export const loadCanvasKit = (deps, config, browserEnvironment, engineRevision)
     const useChromiumCanvasKit = supportsChromiumCanvasKit && (config.canvasKitVariant !== "full");
     let baseUrl = config.canvasKitBaseUrl ?? `https://www.gstatic.com/flutter-canvaskit/${engineRevision}/`;
     if (useChromiumCanvasKit) {
-      baseUrl = `${baseUrl}/chromium/`;
+      baseUrl = `${baseUrl}chromium/`;
     }
     let canvasKitUrl = `${baseUrl}canvaskit.js`;
     if (deps.flutterTT.policy) {