Type confusion in PostgreSQL plperl may allow an object creator to execute arbitrary code, via blessing a non-hash reference into PostgreSQL::InServer::ARRAY. We have not confirmed or ruled out a way to control the pointer sufficiently to achieve security impact, but we are proceeding as though that is possible. Versions before PostgreSQL 18.7, 17.12, 16.16, 15.20, and 14.25 are affected.
Attacker has permission to "CREATE EXTENSION plperl", or another user previously issued that. Attacker has permission to create objects (temporary objects or non-temporary objects in at least one schema).