GlassWire 3.6.859 Random Crashes - Qt5Core.dll Exception 0xc0000409

GlassWire Help
1

GlassWire version 3.6.859 is experiencing frequent random crashes during normal operation. The application crashes occur when:

  • Opening the Settings window
  • Clicking on Traffic Monitor
  • Resizing the window from the bottom-right corner
  • Other random UI interactions

Error Details:

  • Faulting application: GlassWire.exe, version 3.6.859.0
  • Faulting module: Qt5Core.dll, version 5.15.2.0
  • Exception code: 0xc0000409 (stack buffer overrun)
  • Fault offset: 0x0001f081

Additional Observations:

  • Multiple GWCrashpadHandler.exe processes (3) running in Task Manager
  • Crashes are intermittent - the same actions sometimes work, sometimes cause crashes
  • Multiple crash instances with identical error signatures

Critical Impact: This is a high-priority issue IF the crashes compromise the firewall functionality. When GlassWire crashes while running in “Ask to Connect” firewall mode, there’s a risk of unwanted traffic being allowed through, creating a potential security vulnerability.

Clarification Needed: It’s unclear whether the actual firewall functionality runs in a separate process that remains active when the main GlassWire.exe crashes, or if the entire firewall protection goes down with the UI crash. If the firewall runs as a separate service/process and continues blocking traffic even when the UI crashes, this would be a lower priority UI-only issue. However, if the whole firewall protection stops when GlassWire.exe crashes, this becomes a major security vulnerability requiring immediate attention.

Please confirm: Does the firewall protection remain active when the main GlassWire application crashes, or does the entire security functionality shut down with the UI?

System Information:

  • Windows [your Windows version]
  • GlassWire 3.6.859
  • Installation path: C:\Program Files (x86)\GlassWire\

Requested Action: Please investigate and provide information about the firewall service architecture, and if the crashes do affect security functionality, please provide a hotfix for this Qt5Core.dll stability issue as soon as possible.

2

Update:

I’ve conducted additional testing to determine the scope of this issue:

Firewall Functionality Test: I created a test application that connects to the internet every second. During multiple GlassWire crashes, the firewall protection continued to work correctly - blocked connections remained blocked and the “Ask to Connect” prompts still appeared for new connections. This confirms that the actual firewall functionality runs independently of the main UI process and remains active even when GlassWire.exe crashes.

Revised Priority Assessment: Since the core security functionality remains intact during crashes, this is primarily a UI stability issue rather than a critical security vulnerability. However, the frequent crashes are still quite disruptive to normal usage and monitoring capabilities.

Additional Error Pattern: I’m also encountering crashes with a different module:

Faulting application name: GlassWire.exe, version: 3.6.859.0
Faulting module name: CoreMessaging.dll, version: 10.0.26100.4202
Exception code: 0xc00001ad
Fault offset: 0x00014f08

This suggests the stability issues may be broader than just the Qt5Core.dll problem initially reported.

System Information:

  • Windows 11 Version 24H2 (OS Build 26100.4770)
  • GlassWire 3.6.859

Next Steps: I’m attempting a clean reinstallation to see if this resolves the frequent crashes. The combination of Qt5Core.dll and CoreMessaging.dll crashes indicates potential compatibility issues with Windows 11 24H2 system components.

3

Thanks for these insights @beeq. I will share your feedback with the team. Please let us know if a clean reinstall resolves these issues.

1 Like
4

Hi! Ok it seems clean reinstall fixed the issues, and the app is not crashing any longer

5

Glad to hear that! Keep us posted if you run into any issues again.