CVE-2026-78183: critical vulnerability in DBD-Pg

DBD::Pg version 3.21.0 for Perl has a heap out-of-bounds write in quote_float. quote_float() allocates the length of the string + 1, which is the size of the bare numeric symbol plus NULL. But for special literals NaN, Inf, +Inf, -Inf, Infinity, +Infinity, -Infinity it emits the literal surrounded by quotes plus NULL, which is length + 3 bytes. Every recognised literal (case-insensitive) overflows by 2 bytes, a single quote and a NULL. This can be reached by the $dbh->quote method, for example $dbh->quote( "Infinity", DBI::SQL_NUMERIC ). This regression was introduced in 3.21.0 by the quote.c rewrite.