PostgreSQL relation replacement during pg_dump executes arbitrary SQL

Time-of-check Time-of-use (TOCTOU) race condition in pg_dump in PostgreSQL allows an object creator to execute arbitrary SQL functions as the user running pg_dump, which is often a superuser. The attack involves replacing another relation type with a view or foreign table. The attack requires waiting for pg_dump to start, but winning the race condition is trivial if the attacker retains an open transaction. Versions before PostgreSQL 16.4, 15.8, 14.13, 13.16, and 12.20 are affected.