CVE-2005-0004 allows an unprivileged local attacker to create/overwrite files on the machine with the privilege of the user running the mysqlaccess script (e.g.: usually a database administrator or root).
mysqlaccess uses a predictable file naming in /tmp to store temporary data. An attacker could create a symlink with a similar name, pointing elsewhere on the file system structure.

Upstream patch :
http://lists.mysql.com/internals/20600

mitre.org info on the CVE:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=can-2005-0004

Affected versions : MySQL 4.0.23 and earlier, 4.1.x before 4.1.10, 5.0.x before 5.0.3, and other versions including 3.x

Versions shipped in Red Hat are not affected, since they are either using the patched version of mysqlaccess, or are not shipping mysqlaccess script.