The rxvt terminal emulator 2.7.8 and earlier allows attackers to modify the window title via a certain character escape sequence and then insert it back to the command line in the user's terminal, e.g. when the user views a file containing the malicious sequence, which could allow the attacker to execute arbitrary commands.
http://www.securityfocus.com/bid/6953
http://www.securityfocus.com/advisories/5137
http://www.redhat.com/support/errata/RHSA-2003-055.html
http://www.redhat.com/support/errata/RHSA-2003-054.html
http://www.mandrakesoft.com/security/advisories?name=MDKSA-2003:003
http://www.iss.net/security_center/static/11414.php
http://marc.info/?l=bugtraq&m=104612710031920&w=2
http://archives.neohapsis.com/archives/vulnwatch/2003-q1/0093.html