DBI versions before 1.652 for Perl allow a heap out-of-bounds write via an unvalidated numeric placeholder that sets the binder counter in preparse.
preparse reserves seven output bytes per input byte, the width of the longest ':p99999' expansion. The ':N' branch parses the number with atoi(src) and assigns it to the binder counter with no range check, so a statement containing ':2147483648' leaves the counter negative (-2147483648 with glibc, where atoi wraps). Each following '?' then expands through sprintf(start, ":p%d", idx++) to ':p-2147483648', 14 bytes with the terminating NUL where the buffer budgets 7. The placeholder limit added in 1.650 tests the counter against 99,999, which a negative counter passes.
Any caller that preparses an untrusted statement into ':pN' style placeholders gets a heap out-of-bounds write that grows with the number of '?' marks following the poisoned placeholder. The '?' and '%s' return styles compare the parsed number against the expected sequence and error out, and are unaffected.
For deployments that cannot be upgraded, limit SQL statements to 99,999 placeholders.
Upgrade to DBI 1.652 or later.