diff --git a/src/vs/workbench/services/environment/browser/environmentService.ts b/src/vs/workbench/services/environment/browser/environmentService.ts
index 9369ad3a7dcd06a7b1e20a1b83ce4e34b3722924..c043a974ca4e9da329b0a0c20bf31b9b540c2fdc 100644
--- a/src/vs/workbench/services/environment/browser/environmentService.ts
+++ b/src/vs/workbench/services/environment/browser/environmentService.ts
@@ -208,10 +208,14 @@ export class BrowserWorkbenchEnvironmentService implements IWorkbenchEnvironment
 
 	get disableExtensions() { return this.payload?.get('disableExtensions') === 'true'; }
 
+	private get webviewEndpoint(): string {
+		// TODO@matt: get fallback from product.json
+		return this.options.webviewEndpoint || 'https://{{uuid}}.vscode-webview-test.com/{{commit}}';
+	}
+
 	@memoize
 	get webviewExternalEndpoint(): string {
-		// TODO@matt: get fallback from product.json
-		return (this.options.webviewEndpoint || 'https://{{uuid}}.vscode-webview-test.com/{{commit}}').replace('{{commit}}', product.commit || '0d728c31ebdf03869d2687d9be0b017667c9ff37');
+		return (this.webviewEndpoint).replace('{{commit}}', product.commit || '0d728c31ebdf03869d2687d9be0b017667c9ff37');
 	}
 
 	@memoize
@@ -221,7 +225,8 @@ export class BrowserWorkbenchEnvironmentService implements IWorkbenchEnvironment
 
 	@memoize
 	get webviewCspSource(): string {
-		return this.webviewExternalEndpoint.replace('{{uuid}}', '*');
+		const uri = URI.parse(this.webviewEndpoint.replace('{{uuid}}', '*'));
+		return `${uri.scheme}://${uri.authority}`;
 	}
 
 	get disableTelemetry(): boolean { return false; }