CVE-2026-6477 PostgreSQL libpq lo_* functions let server superuser overwrite client stack memory

Use of inherently dangerous function PQfn..., resultisint=0, ... in PostgreSQL libpq loexport, loread, lolseek64, and lotell64 functions allows the server superuser to overwrite a client stack buffer with an arbitrarily-large response. Like gets, PQfn..., resultisint=0, ... stores arbitrary-lengt...