The ioperm system call in Linux kernel 2.4.20 and earlier does not properly restrict privileges, which allows local users to gain read or write access to certain I/O ports.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A278
http://www.turbolinux.com/security/TLSA-2003-41.txt
http://www.redhat.com/support/errata/RHSA-2003-172.html
http://www.redhat.com/support/errata/RHSA-2003-147.html
http://www.mandriva.com/security/advisories?name=MDKSA-2003:074
http://www.mandriva.com/security/advisories?name=MDKSA-2003:066
http://www.debian.org/security/2004/dsa-442
http://www.debian.org/security/2003/dsa-336
http://www.debian.org/security/2003/dsa-332
http://www.debian.org/security/2003/dsa-312
http://www.debian.org/security/2003/dsa-311
http://marc.info/?l=bugtraq&m=105301461726555&w=2
http://archives.neohapsis.com/archives/vulnwatch/2003-q2/0076.html