uudecode, as available in the sharutils package before 4.2.1, does not check whether the filename of the uudecoded file is a pipe or symbolic link, which could allow attackers to overwrite files or execute commands.
http://www.securityfocus.com/bid/4742
http://www.redhat.com/support/errata/RHSA-2003-180.html
http://www.redhat.com/support/errata/RHSA-2002-065.html
http://www.linux-mandrake.com/en/security/2002/MDKSA-2002-052.php
http://www.kb.cert.org/vuls/id/336083
http://www.iss.net/security_center/static/9075.php
http://www.aerasec.de/security/index.html?id=ae-200204-033&lang=en