packet.c in ssh in OpenSSH allows remote attackers to cause a denial of
service (crash) by sending an invalid protocol sequence with
USERAUTH_SUCCESS before NEWKEYS, which causes newkeys[mode] to be NULL.
An unspecified vulnerability in portable OpenSSH before 4.4, when running
on some platforms, allows remote attackers to determine the validity of
usernames via unknown vectors involving a GSSAPI "authentication abort."
