CVE 2007-3279
PostgreSQL 8.1 and probably later versions, when the PL/pgSQL (plpgsql) language has been created, grants certain plpgsql privileges to the PUBLIC domain, which allows remote attackers to create and execute functions, as demonstrated by functions that perform local brute-force password guessing attacks, which may evade intrusion detection.
See the
CVE page on Mitre.org
for more details.