DBI versions before 1.654 for Perl incorrectly treat numeric values as strings in FetchHashKeyName. fetchrow_hashref uses the string pointer of the FetchHashKeyName attribute as the key name without stringifying it first. When FetchHashKeyName has been set to an integer (IV) or floating-point (NV) value, that pointer is invalid, so reading the key name triggers a segmentation fault. This can be triggered with the following code: my $dbh = DBI->connect( "dbi:ExampleP:", "", "", { RaiseError => 0, PrintError => 0 } ); $dbh->{FetchHashKeyName} = 42; my $sth = $dbh->prepare("select mode, size, name from ."); $sth->execute; $sth->fetchrow_hashref;