CREATE TRIGGER in PostgreSQL 8.3.x before 8.3.18, 8.4.x before 8.4.11, 9.0.x before 9.0.7, and 9.1.x before 9.1.3 does not properly check the execute permission for trigger functions marked SECURITY DEFINER, which allows remote authenticated users to execute otherwise restricted triggers on arbitrary data by installing the trigger on an attacker-owned table.