[Problem/Bug]: BrowserProcess crashes with exit code -2147483645 when canceling the FrameNavigationStarting event (for a particular site)

[pushkin-]

What happened?

When canceling the FrameNavigationStarting event of certain sites, the browser process crashes. Exit code: -2147483645

Importance

Important. My app's user experience is significantly compromised.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

129.0.2792.65

SDK Version

1.0.2535.41

Framework

Winforms

Operating System

Windows 11

OS Version

22631.4169

Repro steps

modify the WinForms sample webview2 app as follows:

1. Iin WebView2Control_CoreWebView2InitializationCompleted, add: this.webView2Control.CoreWebView2.NewWindowRequested += CoreWebView2_NewWindowRequested;
2. make that handler create the webview2 itself and add a FrameNavigationStarting handler:

	private async void CoreWebView2_NewWindowRequested(object sender, CoreWebView2NewWindowRequestedEventArgs e)
	{
		e.Handled = true;
		using (e.GetDeferral())
		{
			Form form = new Form();
			WebView2 webView = new WebView2();
			await webView.EnsureCoreWebView2Async();
			form.Controls.Add(webView);

			webView.CoreWebView2.FrameNavigationStarting += CoreWebView2_FrameNavigationStarting;
			form.Visible = true;
			webView.Dock = DockStyle.Fill;
			e.NewWindow = webView.CoreWebView2;
		}
	}

3. set the FrameNavigationStarting handler to:

	private void CoreWebView2_FrameNavigationStarting(object sender, CoreWebView2NavigationStartingEventArgs e)
	{
		if (e.Uri.StartsWith("https://smartscreentestratings.com/xplt_100_0_0.html"))
		{
			e.Cancel = true;
		}
	}

1. start app and navigate to https://demo.smartscreen.msft.net/
2. scroll down and click the Malvertising link (which will open a window to https://demo.smartscreen.msft.net/other/exploit_frame.html)
3. observe browser process crashes

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

No, this never worked

Last working version (if regression)

No response

AB#54319772

[LiangTheDev]

Thanks for reporting the issue. I've filed an internal work item to track and investigate.