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."

The tsearch2 module in PostgreSQL 7.4 through 8.0.x declares the (1) dex_init, (2) snb_en_init, (3) snb_ru_init, (4) spell_init, and (5) syn_init functions as "internal" even when they do not take an internal argument, which allows attackers to cause a denial of service (application crash) and possibly have other impacts via SQL commands that call other functions that accept internal arguments.