I cannot reproduce this on Debian unstable with either 2.2.22-9 or 2.2.22-1.
Wild guess: Do you have a per-user process limit configured in /etc/security/limits.conf ?
If no, it would be helpful if you could provide a backtrace of the process that curl connects to and hangs. There is some documentation about how to do that in
/usr/share/doc/apache2.2-common/README.backtrace. But the doc is for Debian. For Ubuntu, the installing of the debugging symbols works differently (maybe someone else can provide a pointer).