diff --git a/src/vs/workbench/services/extensions/worker/webWorkerExtensionHostIframe.html b/src/vs/workbench/services/extensions/worker/webWorkerExtensionHostIframe.html
index 52045f22ae4..3983bdb9dd4 100644
--- a/src/vs/workbench/services/extensions/worker/webWorkerExtensionHostIframe.html
+++ b/src/vs/workbench/services/extensions/worker/webWorkerExtensionHostIframe.html
@@ -4,7 +4,7 @@
 		<meta http-equiv="Content-Security-Policy" content="
 			default-src 'none';
 			child-src 'self' data: blob:;
-			script-src 'self' 'unsafe-eval' 'sha256-V28GQnL3aYxbwgpV3yW1oJ+VKKe/PBSzWntNyH8zVXA=' https: http://localhost:*;
+			script-src 'self' 'unsafe-eval' 'sha256-V28GQnL3aYxbwgpV3yW1oJ+VKKe/PBSzWntNyH8zVXA=' https: http://localhost:* blob:;
 			connect-src 'self' https: wss: http://localhost:* http://127.0.0.1:* ws://localhost:* ws://127.0.0.1:*;"/>
 	</head>
 	<body>
