The web address I've quoted is (obviously) not the real one - it's an internal server so you couldn't connect to it even if I put the real address in there. The "Trac" bit is real. The web site is "Powered by Trac 1.2.2 by Edgewall Software" (https://trac.edgewall.org/)Authentication Required. https://example.com is requesting your username and a password. The site says: "Trac"
I type in my username and password, and Pale Moon 28.0.0 crashes with:
Pale Moon web browser has stopped working.
Problem signature:
Problem Event Name: APPCRASH
Application Name: palemoon.exe
Application Version: 4.1.4.6793
Application Timestamp: 5b699ef8
Fault Module Name: xul.dll
Fault Module Version: 4.1.4.6793
Fault Module Timestamp: 5b69a0d6
Exception Code: c0000005
Exception Offset: 00000000004e43b5
OS Version: 6.1.7601.2.1.0.256.1
Locale ID: 3081
Additional Information 1: ccce
Additional Information 2: ccce36c26b4c307d6f789697c90040f9
Additional Information 3: f5bc
Additional Information 4: f5bcadc4d75510188cd92fdb3aab40c8
28.0.0.1 does not fix the problem. It fails much the same way, and says:
Problem signature:
Problem Event Name: APPCRASH
Application Name: palemoon.exe
Application Version: 4.1.4.6812
Application Timestamp: 5b82db07
Fault Module Name: xul.dll
Fault Module Version: 4.1.4.6812
Fault Module Timestamp: 5b82ddcb
Exception Code: c0000005
Exception Offset: 00000000004de485
OS Version: 6.1.7601.2.1.0.256.1
Locale ID: 3081
Additional Information 1: ccce
Additional Information 2: ccce36c26b4c307d6f789697c90040f9
Additional Information 3: 30e1
Additional Information 4: 30e13d837cb179184a83939e970e3a3a
It doesn't crash every time, but quite often - at least half of the time. There's no obvious conditions that correlate to its crashing or not.
After I click OK on the Authentication dialog, Pale Moon always asks me "would you like Pale Moon to remember this login" (I always ignore that prompt, for the purposes of reproducing the problem), but never shows any of the web page, not does it clear the window of the previous page (if there was one) from that tab. It sometimes says "Secure Connection Failed. The connection to the server was reset while the page was loading." first, then crashes (or not) after I click Try Again. Again, there's no obvious correlation between that message and whether or not I connect or crash.
I can reproduce the problem on two different PCs:
my work PC, Windows 7 SP1 64-bit, Pale Moon 64-bit
A VirtualBox virtual machine on my home PC, with Windows 7 SP1 64-bit (both host and guest), and Open VPN (on the VM) to connect to the office network.
Unfortunately it's an internal company website, which means you can't use it to replicate the problem. I've seen the Authentication dialog on several different companies' servers, but I don't know of any publicly visible website that does it.