OpenSSH 4.4 was released and mentions:
* On portable OpenSSH, fix a GSSAPI authentication abort that
could be used to determine the validity of usernames on some
Created attachment 151319 [details]
Backport of a patch from 4.4.p1
openssh-4.3p2-19.fc6 has been pushed for fc6, which should resolve this issue. If these problems are still present in this version, then please make note of it in this bug report.