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.