Browser control crashes as soon as a Url is loaded when the Host application itself is launched from a browser

[rhoney]

Is there an existing issue for this?

• I have searched both open/closed issues, no issue already exists.

CefSharp Version

137.0.100

Operating System

Windows 10

Architecture

x64

.Net Version

4.7.2

Implementation

WPF

Reproduction Steps

We have a WPF application that gets launched from the browser. After initialising CefSharp, the application tries to load websites as per configuration.
This used to work until CefSharp version 126. However all versions of CefSharp since 127 crash as soon as the application is launched from the browser and it tries to load any website inside a CefSharp WPF browser control.

For clarity, the same works if the application is launched directory from File Explorer.

Here are the steps to reproduce:

WpfApp1.zip

1. From the attached zip, extract and build the WpfApp1 project using Visual Studio.
2. Copy the output file path (full absolute path of WpfApp1.exe) in the tccldp.reg registry file present in the zip file attached. This is a very safe .reg file which basically registers a protocol tccldp allowing WpfApp1 to be launched from any browser on a Windows machine.
3. Afterwards, open index.html from the zip file in any browser, and click the only button on the screen.
4. Acknowledge any browser pop-up to launch WpfApp1 and allow it to be launched from the browser.

You would notice the WpfApp1 launches and then crashes right at the moment where it loads a url in the CefSharp browser.

The crash log from Windows Event Log is here:

Faulting application name: WpfApp1.exe, version: 1.0.0.0, time stamp: 0xe59f4217
Faulting module name: libcef.dll, version: 137.0.10.0, time stamp: 0x683a0cc2
Exception code: 0x80000003
Fault offset: 0x0000000001a20684
Faulting process id: 0x91a4
Faulting application start time: 0x01dbde001d1ab4d7
Faulting application path: D:\Projects\Travcom\ClientLinq\Server\master\AddOns\WpfApp1\bin\Debug\WpfApp1.exe
Faulting module path: D:\Projects\Travcom\ClientLinq\Server\master\AddOns\WpfApp1\bin\Debug\x64\libcef.dll
Report Id: 72eb1b05-ed55-4875-9ed5-70774fbe07cb
Faulting package full name:
Faulting package-relative application ID:

Like I said, this used to work and still works up and until CefSharp 126 version. The commented code MainWindow1.xaml.cs would underline the options and flags we tried to work with to make this work. But it fails consistently.

The interesting part is the app works when directly launched from File Explorer.

Expected behavior

The app should work and CefSharp's Wpf Browser control should be able to open the website when the Host app is launched from browser also.

Actual behavior

The app crashes unfortunately on all Windows 10 and Windows 11 machines we tried including launching from Chrome / Edge normal tab as well as Incognito / Private tab.

Regression?

Yes, this used to work until CefSharp 126 version.

Known Workarounds

Downgrade to CefSharp 126 version for now.

Does this problem also occur in the CEF Sample Application

Not Tested

Other information

No response

[amaitland]

It sounds like your working directory isn't set correctly.

Please no links to binaries, e.g. zip files, either contribute your example as a github project, a gist or another public code sharing service.

As per https://github.com/cefsharp/CefSharp/blob/master/CONTRIBUTING.md#help-us-help-you

Faulting module name: libcef.dll, version: 137.0.10.0, time stamp: 0x683a0cc2

Crashes in libcef.dll are very very rarely bugs in CefSharp. Did you check the log file for errors?

This is more likely a support issue than a bug.

[rhoney]

@amaitland Here's the repo with repro steps as outlined above:
https://github.com/rhoney/WpfApp1

Yes, I checked log files. No log was there except the Windows Event Log entry. I believe I created dumps too. Here's a dump file:
https://drive.google.com/file/d/1W3p7NOglYasV1cCVqKtrO8gzo7t0IVG1/view?usp=sharing
(apologies, too large for uploading to GitHub repo, so sharing as G Drive link).

Please note as I mentioned, the crash only happens when the app is launched from browser. It does not happen when app is launched directly from File Explorer.

[amaitland]

https://learn.microsoft.com/en-us/dotnet/api/system.io.directory.getcurrentdirectory?view=net-9.0

What is the working directory when it works and when it doesn't work?

[amaitland]

Yes, I checked log files. No log was there except the Windows Event Log entry. I believe I created dumps too. Here's a dump file:
https://drive.google.com/file/d/1W3p7NOglYasV1cCVqKtrO8gzo7t0IVG1/view?usp=sharing
(apologies, too large for uploading to GitHub repo, so sharing as G Drive link).

You can load the symbols and get a stack trace.

https://github.com/cefsharp/CefSharp/wiki/Trouble-Shooting#loading-native-symbols-for-easier-diagnosis

[xinq05679]

I have the same issue.

I find that when using the URL protocol from the browser to run the application, its working directory will be 'C:\Windows\System32'

This causes the application to crash...

If I change the working directory to a different path in the Program.cs file before the application runs, the application will run perfectly.

Environment.CurrentDirectory = "Other path";

MainForm = new MainForm();
Application.Run(MainForm )

[amaitland]

Thanks for confirming! This is basically what I expected.