Xinetd is a secure replacement for Red Hat's inetd, the Internet services daemon.
Versions of Xinetd prior to 2.3.7 leak file descriptors for the signal pipe to services that are launched by xinetd. This could allow an attacker to execute a DoS attack via the pipe. A Red Hat avdisory sugguest users to upgrade to the errata packages which fix the vulnerability.
More information can be found here.