When I turned on the checkbox 'Validate access for modules that are commonly abused by explots' (thank you for suggeting it, Tom), I got a crash of exception 0xc0000409 from the browser process on Win10 1903. Wish I had the skills and time to help support EAF instead of just turning it off, but Firefox is useful enough to me I will continue to use it (though less often) with this protection turned off, and hope this post helps others. I did have to repeat this process after Firefox auto-updated to a new version as well. I expect turning it off entirely would also help. I just switched on ' Audit only' and it stopped the crashes. Scroll down to Export address filtering (EAF) Switch from the System settings to the Program settings tabįind firefox.exe among the programs to customize, Click to expand, then click Edit Scroll down to the Exploit protection section, and click on Exploit protection settings Windows Security control panel, go to App & browser control

In case it helps others, until such time as someone can help support EAF mitigations, Here's the GUI method I used (Powershell commandlet to do the same seems to have a bug filed against it at this time) Thanks to this thread pointing me to Export Address Filtering (EAF), I was able to find a workaround of placing that protection into Audit mode. I'm experiencing the same crashes with the same exception code of 0xc0000409 and fault offset of 0x000000000003b614 I found this bug report when searching for why my Firefox was crashing on Windows 10 1809

Event id 1000 iexplore.exe ntdll.dll