GNU tar 1.13.19 and other versions before 1.13.25 allows remote attackers to overwrite arbitrary files via a symlink attack, as the result of a modification that effectively disabled the security check.
http://www.redhat.com/support/errata/RHSA-2002-096.html
http://www.openpkg.com/security/advisories/OpenPKG-SA-2006.038.html
http://www.mandriva.com/security/advisories?name=MDKSA-2006:219