OpenSSH is OpenBSD's SSH (Secure SHell) protocol implementation.
An error in the way OpenSSH handled GSSAPI credential delegation was discovered. OpenSSH as distributed with Red Hat Enterprise Linux 4 contains support for GSSAPI user authentication, typically used for supporting Kerberos. On OpenSSH installations which have GSSAPI enabled, this flaw could allow a user who sucessfully authenticates using a method other than GSSAPI to be delegated with GSSAPI credentials. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2005-2798 to this issue.
Additionally, the following bugs have been addressed:
The ssh command incorrectly failed when it was issued by the root user with a non-default group set.
The sshd daemon could fail to properly close the client connection if multiple X clients were forwarded over the connection and the client session exited.
The sshd daemon could bind only on the IPv6 address family for X forwarding if the port on IPv4 address family was already bound. The X forwarding did not work in such cases.
This update also adds support for recording login user IDs for the auditing service. The user ID is attached to the audit records generated from the user's session.
All users of openssh should upgrade to these updated packages, which contain backported patches to resolve these issues.