MySQL is a fast, multi-threaded, multi-user SQL database server.
Javier Fernandez-Sanguino Pena from the Debian Security Audit Project discovered that the 'mysqlaccess' script creates temporary files in world-writeable directories with predictable names.
A local attacker could create symbolic links in the temporary files directory, pointing to a valid file somewhere on the filesystem. When the mysqlaccess script is executed, this would result in the file being overwritten with the rights of the user running the software, which could be the root user.
There is no known workaround at this time.
All MySQL users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-db/mysql-4.0.22-r2"