PostgreSQL 7.3.x through 8.0.x gives public EXECUTE access to certain character conversion functions, which allows unprivileged users to call those functions with malicious values, with unknown impact, aka the "Character conversion vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A676
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10050
http://www.vupen.com/english/advisories/2005/0453
http://www.securityfocus.com/bid/13476
http://www.securityfocus.com/archive/1/426302/30/6680/threaded
http://www.redhat.com/support/errata/RHSA-2005-433.html
http://www.postgresql.org/about/news.315
http://www.novell.com/linux/security/advisories/2005_36_sudo.html
http://archives.postgresql.org/pgsql-announce/2005-05/msg00001.php