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perl-5.44.0
⭐ Starred 2013 / parent
Security Advisories (1)
CVE-2026-15534 (2026-08-09)

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

NAME

parent - Establish an ISA relationship with base classes at compile time

SYNOPSIS

package Baz;
use parent qw(Foo Bar);

DESCRIPTION

Allows you to both load one or more modules, while setting up inheritance from those modules at the same time. Mostly similar in effect to

package Baz;
BEGIN {
    require Foo;
    require Bar;
    push @ISA, qw(Foo Bar);
}

By default, every base class needs to live in a file of its own. If you want to have a subclass and its parent class in the same file, you can tell parent not to load any modules by using the -norequire switch:

package Foo;
sub exclaim { "I CAN HAS PERL" }

package DoesNotLoadFooBar;
use parent -norequire, 'Foo', 'Bar';
# will not go looking for Foo.pm or Bar.pm

This is equivalent to the following code:

package Foo;
sub exclaim { "I CAN HAS PERL" }

package DoesNotLoadFooBar;
push @DoesNotLoadFooBar::ISA, 'Foo', 'Bar';

This is also helpful for the case where a package lives within a differently named file:

package MyHash;
use Tie::Hash;
use parent -norequire, 'Tie::StdHash';

This is equivalent to the following code:

package MyHash;
require Tie::Hash;
push @ISA, 'Tie::StdHash';

If you want to load a subclass from a file that require would not consider an eligible filename (that is, it does not end in either .pm or .pmc), use the following code:

package MySecondPlugin;
require './plugins/custom.plugin'; # contains Plugin::Custom
use parent -norequire, 'Plugin::Custom';

HISTORY

This module was forked from base to remove the cruft that had accumulated in it.

CAVEATS

SEE ALSO

base
parent::versioned

A fork of parent that provides version checking in parent class modules.

AUTHORS AND CONTRIBUTORS

Rafaël Garcia-Suarez, Bart Lateur, Max Maischein, Anno Siegel, Michael Schwern

MAINTAINER

Max Maischein corion@cpan.org

Copyright (c) 2007-2017 Max Maischein <corion@cpan.org> Based on the idea of base.pm, which was introduced with Perl 5.004_04.

LICENSE

This module is released under the same terms as Perl itself.