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perl-5.40.2
⭐ Starred 2013 / Devel::PPPort
Security Advisories (7)
CVE-2026-13221 (2026-07-13)

Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.10 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk. When such branches are combined into a trie, the delta between the first branch and the shared tail is stored in a 16-bit field. A branch count above 65535 overflows the field, and the trie's match decision table is truncated with no warning or error. A pattern of this shape produces false positive matches (matching strings it should not) and false negative matches (failing to match strings it should). When such a pattern gates an access or filtering decision, the result is wrong.

CVE-2026-19487 (2026-08-13)

Perl versions from 5.9.4 before 5.41.9 produce incorrect regular expression match results when a stale failure flag ends the Aho-Corasick prescan early in S_find_byclass. The prescan walks the subject for positions where the full pattern could match, and the engine tries it from the leftmost one recorded. A failing transition sets the failed flag, and a later successful transition does not clear it, so the prescan reads the stale flag as a failure and stops before it can record a candidate that starts earlier. It takes a subject where one candidate is recorded and a later character then forces a fallback through a fail link that succeeds. Example: "ABCDE" =~ m/ABCF|BCDE|C/; # matches C at offset 2, not BCDE "ABCDE" =~ m/ABCF|BCDE|C(G)/; # no match, BCDE missed An alternation like this can miss input it should match, or match it on the wrong branch, so an access or filtering decision made from the result can be wrong.

CVE-2025-40909 (2025-05-30)

Perl threads have a working directory race condition where file operations may target unintended paths. If a directory handle is open at thread creation, the process-wide current working directory is temporarily changed in order to clone that handle for the new thread, which is visible from any third (or more) thread already running. This may lead to unintended operations such as loading code or accessing files from unexpected locations, which a local attacker may be able to exploit. The bug was introduced in commit 11a11ecf4bea72b17d250cfb43c897be1341861e and released in Perl version 5.13.6

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.

CVE-2026-4176 (2026-03-29)

Perl versions from 5.9.4 before 5.40.4-RC1, from 5.41.0 before 5.42.2-RC1, from 5.43.0 before 5.43.9 contain a vulnerable version of Compress::Raw::Zlib. Compress::Raw::Zlib is included in the Perl package as a dual-life core module, and is vulnerable to CVE-2026-3381 due to a vendored version of zlib which has several vulnerabilities, including CVE-2026-27171. The bundled Compress::Raw::Zlib was updated to version 2.221 in Perl blead commit c75ae9cc164205e1b6d6dbd57bd2c65c8593fe94.

CVE-2026-57432 (2026-07-13)

Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.11 have an integer overflow in S_measure_struct leading to an out-of-bounds heap read in pack and unpack. S_measure_struct adds each item's size times its repeat count to a running total with no overflow check, so a large repeat count in a pack or unpack template wraps the signed SSize_t total negative. The @, X, and x position codes then guard their moves with a signed length comparison that passes when the length is negative, advancing the buffer pointer out of bounds. A template derived from untrusted input can read heap memory past the buffer and return it to the caller.

CVE-2026-8376 (2026-05-25)

Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.11 have a heap buffer overflow when compiling regular expressions with a repeated fixed string on 32-bit builds. Perl_study_chunk in regcomp_study.c checked the size of the joined substring buffer in characters rather than bytes. For a quantified fixed substring with a large minimum count, the byte length mincount * l could overflow SSize_t, producing an undersized SvGROW allocation; the subsequent copy writes past the end of the buffer. A caller that compiles an attacker-controlled regular expression on a 32-bit perl build triggers a heap buffer overflow at compile time.

NAME

Devel::PPPort - Perl/Pollution/Portability

SYNOPSIS

Devel::PPPort::WriteFile();   # defaults to ./ppport.h
Devel::PPPort::WriteFile('someheader.h');

# Same as above but retrieve contents rather than write file
my $contents = Devel::PPPort::GetFileContents();
my $contents = Devel::PPPort::GetFileContents('someheader.h');

Start using Devel::PPPort for XS projects

$ cpan Devel::PPPort
$ perl -MDevel::PPPort -e'Devel::PPPort::WriteFile'
$ perl ppport.h --compat-version=5.6.1 --patch=diff.patch *.xs
$ patch -p0 < diff.patch
$ echo ppport.h >>MANIFEST

DESCRIPTION

Perl's API has changed over time, gaining new features, new functions, increasing its flexibility, and reducing the impact on the C namespace environment (reduced pollution). The header file written by this module, typically ppport.h, attempts to bring some of the newer Perl API features to older versions of Perl, so that you can worry less about keeping track of old releases, but users can still reap the benefit.

Devel::PPPort contains two functions, WriteFile and GetFileContents. WriteFile's only purpose is to write the ppport.h C header file. This file contains a series of macros and, if explicitly requested, functions that allow XS modules to be built using older versions of Perl. Currently, Perl versions from __MIN_PERL__ to __MAX_PERL__ are supported.

GetFileContents can be used to retrieve the file contents rather than writing it out.

This module is used by h2xs to write the file ppport.h.

Why use ppport.h?

You should use ppport.h in modern code so that your code will work with the widest range of Perl interpreters possible, without significant additional work.

You should attempt to get older code to fully use ppport.h, because the reduced pollution of newer Perl versions is an important thing. It's so important that the old polluting ways of original Perl modules will not be supported very far into the future, and your module will almost certainly break! By adapting to it now, you'll gain compatibility and a sense of having done the electronic ecology some good.

How to use ppport.h

Don't direct the users of your module to download Devel::PPPort. They are most probably not XS writers. Also, don't make ppport.h optional. Rather, just take the most recent copy of ppport.h that you can find (e.g. by generating it with the latest Devel::PPPort release from CPAN), copy it into your project, adjust your project to use it, test it, and distribute the header along with your module.

It is important to use the most recent version of ppport.h. You do need to test before shipping a newer version than you already had. One possible failure is that someone had to convert a backported element from a macro into a function, and actual functions must be enabled with a NEED macro to minimize the possibility of namespace pollution. See HACKERS for details. The developers of Devel::PPPort want to hear if there are other problems that arise from using a later ppport.h. Use https://github.com/Dual-Life/Devel-PPPort/issues to report any.

Running ppport.h

But ppport.h is more than just a C header. It's also a Perl script that can check your source code. It will suggest hints and portability notes, and can even make suggestions on how to change your code. You can run it like any other Perl program:

perl ppport.h [options] [files]

It also has embedded documentation, so you can use

perldoc ppport.h

to find out more about how to use it.

FUNCTIONS

WriteFile

WriteFile takes one optional argument. When called with one argument, it expects to be passed a filename. When called with no arguments, it defaults to the filename ppport.h.

The function returns a true value if the file was written successfully. Otherwise it returns a false value.

GetFileContents

GetFileContents behaves like WriteFile above, but returns the contents of the would-be file rather than writing it out.

COMPATIBILITY

ppport.h supports Perl versions from __MIN_PERL__ to __MAX_PERL__ in threaded and non-threaded configurations.

Provided Perl compatibility API

The header file written by this module, typically ppport.h, provides access to the following elements of the Perl API that are not otherwise available in Perl releases older than when the elements were first introduced. (Note that many of these are not supported all the way back to __MIN_PERL__, but it may be that they are supported back as far as you need; see "Supported Perl API, sorted by version" for that information.)

__PROVIDED_API__

Supported Perl API, sorted by version

The table in this section lists all the Perl API elements available, sorted by the version in which support starts. This includes all the elements that ppport.h helps out with, as well as those elements that it doesn't.

In some cases, it doesn't make practical sense for elements to be supported earlier than they already are. For example, UTF-8 functionality isn't provided prior to the release where it was first introduced.

But in other cases, it just is that no one has implemented support yet. Patches welcome! Some elements are ported backward for some releases, but not all the way to __MIN_PERL__.

If an element, call it ELEMENT, is not on this list, try using this command to find out why:

perl ppport.h --api-info=ELEMENT

A few of the entries in the list below are marked as DEPRECATED. You should not use these for new code, and should be converting existing uses to use something better.

Some of the entries in the list are marked as "experimental". This means these should not generally be used. They may be removed or changed without notice. You can ask why they are experimental by sending email to mailto:perl5-porters@perl.org.

And some of the entries are marked as "undocumented". This means that they aren't necessarily considered stable, and could be changed or removed in some future release without warning. It is therefore a bad idea to use them without further checking. It could be that these are considered to be for perl core use only; or it could be, though, that Devel::PPPort doesn't know where to find their documentation, or that it's just an oversight that they haven't been documented. If you want to use one, and potentially have it backported, first send mail to mailto:perl5-porters@perl.org.

__UNSUPPORTED_API__

BUGS

If you find any bugs, Devel::PPPort doesn't seem to build on your system, or any of its tests fail, please send a bug report to https://github.com/Dual-Life/Devel-PPPort/issues/new.

AUTHORS

  • Version 1.x of Devel::PPPort was written by Kenneth Albanowski.

  • Version 2.x was ported to the Perl core by Paul Marquess.

  • Version 3.x was ported back to CPAN by Marcus Holland-Moritz.

  • Versions >= 3.22 are maintained by perl5 porters

COPYRIGHT

Version 3.x, Copyright (C) 2004-2013, Marcus Holland-Moritz.

Copyright (C) 2018-2020, The perl5 porters

Version 2.x, Copyright (C) 2001, Paul Marquess.

Version 1.x, Copyright (C) 1999, Kenneth Albanowski.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

See h2xs, ppport.h.