I’ve also had a handful of reports of 3.0 segfaulting. Hitherto none of the reporters has responded to my requests for a test case, and I wasn’t able to reproduce it. So no fix.
Yesterday evening when I was out, I got the email that nailed it. My client on a mostly-different job is using mod_proxy_html 3, and reported a URL that returned a blank browser screen through the proxy. Today I tested it myself, and finally traced what is almost certainly the bug. And it’s one of those “duh” moments: I’d already had to fix the same bug in other modules including mod_proxy_html 2.5.
So anyone using mod_proxy_html and prepared to test-drive an update, please download the update (svn r87 or up) and give it a try!