A vulnerability has been discovered and corrected in krb5-appl,
heimdal and netkit-telnet:

An unauthenticated remote attacker can cause a buffer overflow and
probably execute arbitrary code with the privileges of the telnet
daemon (CVE-2011-4862).

In Mandriva the telnetd daemon from the netkit-telnet-server package
does not have an initscript to start and stop the service, however
one could rather easily craft an initscript or start the service by
other means rendering the system vulnerable to this issue.

The updated packages have been patched to correct this issue.