Open Bug 1706038 Opened 2 years ago Updated 1 year ago

Crash in [@ npwzwmc64.dll | GetModuleHandleW] (WinZip Courier)


(External Software Affecting Firefox :: Other, defect, P3)

Windows 10


(Not tracked)


(Reporter: gsvelto, Unassigned)


(Keywords: crash)

Crash Data

Crash report:


Top 6 frames of crashing thread:

0 npwzwmc64.dll npwzwmc64.dll@0x7d7f 
1 kernelbase.dll GetModuleHandleW 
2 npwzwmc64.dll npwzwmc64.dll@0x47ff 
3 kernel32.dll BaseThreadInitThunk 
4 ntdll.dll RtlUserThreadStart 
5 kernelbase.dll TerminateProcessOnMemoryExhaustion 

This is WinZip Courrier doing something that crashes Firefox. Maybe it's injecting itself in the file picker? It's hard to tell from the stacks.

I downloaded the product from and debugged the behavior. I didn't have a luck to reproduce the crash, though.

WinZip Courier has a Firefox extension. Once I install and enable it, it launches its own process wzwmcffnm.exe and npwzwmc64.exe. The latter one wzwmcffnm64.exe injects npwzwmc64.dll into our browser process via CreateRemoteThread technique to customize the common file dialog.

For the "[ @ npwzwmc64.dll | GetModuleHandleW ]" crash, I think it happens during shutdown. Their code tried to use a pointer in a global variable in npwzwmc64.dll, but it was already set to null. This may be a timing issue that not every WinZip user hits.

According to, I sent an email to WinZip.

Summary: Crash in [@ npwzwmc64.dll | GetModuleHandleW] → Crash in [@ npwzwmc64.dll | GetModuleHandleW] (WinZip Courier)
Severity: -- → S2
Priority: -- → P3
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