User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

Open the PoC under Microsoft Windows [Version 10.0.17763.592] with Firefox 68.0 beta 32-bit

Actual results:

Firefox quits, this can be be used as Denial of Service

Expected results:

Show the yellow bar that the website slows Firefox and not quit.

http://127.0.0.1 is an empty file.

Can you link to a submitted crashreport from about:crashes that corresponds to the crash you're seeing with your testcase?

One of those would be https://crash-stats.mozilla.org/report/index/64f37572-5086-456c-bad8-8dbde0190703

Delay that, not sure that one was done with empty profile.
This one surely is: https://crash-stats.mozilla.org/report/index/aabc4e38-10ad-4fb7-a29d-2c1e20190703

Both of those are OOM crashes (ie we ran out of memory). One of them in the content process (so that would have shown up as a tab crash, not taking down Firefox's "main" process). The other one has no symbols for some reason? Either way, it looks like this is basically memory exhaustion.

It looks like this test case is jamming a large string into the src field of an iframe, so I'll move this to DOM.