Updated telnet packages that fix two buffer overflow vulnerabilities are now available. This update has been rated as having important security impact by the Red Hat Security Response Team.
The telnet package provides a command line telnet client. The telnet-server package includes a telnet daemon, telnetd, that supports remote login to the host machine. Two buffer overflow flaws were discovered in the way the telnet client handles messages from a server. An attacker may be able to execute arbitrary code on a victim's machine if the victim can be tricked into connecting to a malicious telnet server. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the names CAN-2005-0468 and CAN-2005-0469 to these issues. Additionally, the following bugs have been fixed in these erratum packages for Red Hat Enterprise Linux 2.1 and Red Hat Enterprise Linux 3: - telnetd could loop on an error in the child side process - There was a race condition in telnetd on a wtmp lock on some occasions - The command line in the process table was sometimes too long and caused bad output from the ps command - The 8-bit binary option was not working Users of telnet should upgrade to this updated package, which contains backported patches to correct these issues. Red Hat would like to thank iDEFENSE for their responsible disclosure of this issue.