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perl-5.43.1
⭐ Starred 2013 / perldelta
Security Advisories (2)
CVE-2026-8376 (2026-05-25)

Perl versions through 5.43.10 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.

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.

NAME

perldelta - what is new for perl v5.43.1

DESCRIPTION

This document describes differences between the 5.43.0 release and the 5.43.1 release.

If you are upgrading from an earlier release such as 5.42.0, first read perl5430delta, which describes differences between 5.42.0 and 5.43.0.

Modules and Pragmata

Updated Modules and Pragmata

Diagnostics

The following additions or changes have been made to diagnostic output, including warnings and fatal error messages. For the complete list of diagnostic messages, see perldiag.

Changes to Existing Diagnostics

  • Use of uninitialized value%s

    This warning was issued in the reverse order (right-to-left) when both operands of a binary operator are uninitialized values. This is now fixed to be consistent with evaluation order of operands.

Internal Changes

  • The XS parser, ExtUtils::ParseXS, has been extensively restructured internally. Most of these changes shouldn't be visible externally, but might affect XS code which was using invalid or unsupported syntax.

Selected Bug Fixes

  • When both operands of arithmetic operators (+, -, etc.) are overloaded objects which have no method for that operator but have a 0+ method and the fallback option set to TRUE, perl will normally call the 0+ method for the left operand first and then call one for the right operand, i.e. in the same order with operand evaluation order. But if use integer; is in effect, the 0+ methods used to be called in wrong (reverse) order.

Obituary

"WELL VOLUNTEERED!" echoed across conference rooms and IRC channels. Matt S. Trout's battle cry that transformed reluctant volunteers into community leaders.

With profound sadness, we announce Matt's passing. Since the early 2000s, Matt shaped Perl through sheer force of will: IRC operator, PAUSE administrator, Shadowcat Systems co-founder, architect of DBIx::Class. His opinions came wrapped in profanity and delivered at maximum volume. He suffered no fools and grew to sometimes realize he should apologize. Yet this same abrasive exterior protected fierce dedication to mentoring, developers he harangued into volunteering now lead the community themselves. Matt's deliberately mind-bending code pushed Perl forward. Every modern Perl developer touches his legacy daily.

Well volunteered, Matt. Rest in peace.

Acknowledgements

Perl 5.43.1 represents approximately 2 weeks of development since Perl 5.43.0 and contains approximately 15,000 lines of changes across 410 files from 21 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 12,000 lines of changes to 360 .pm, .t, .c and .h files.

Perl continues to flourish into its fourth decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.43.1:

Alexander Karelas, Chad Granum, Chris 'BinGOs' Williams, Chris Prather, Dagfinn Ilmari Mannsåker, Dan Book, Daniel Dragan, Daniel Laügt, Dave Cross, David Mitchell, James E Keenan, Karen Etheridge, Karl Williamson, Leon Timmermans, Paul Evans, Philippe Bruhat (BooK), Richard Leach, Štěpán Němec, TAKAI Kousuke, Thibault Duponchelle, Tony Cook.

The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.

Many of the changes included in this version originated in the CPAN modules included in Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.

For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl source distribution.

Reporting Bugs

If you find what you think is a bug, you might check the perl bug database at https://github.com/Perl/perl5/issues. There may also be information at https://www.perl.org/, the Perl Home Page.

If you believe you have an unreported bug, please open an issue at https://github.com/Perl/perl5/issues. Be sure to trim your bug down to a tiny but sufficient test case.

If the bug you are reporting has security implications which make it inappropriate to send to a public issue tracker, then see "SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec for details of how to report the issue.

Give Thanks

If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, you can do so by running the perlthanks program:

perlthanks

This will send an email to the Perl 5 Porters list with your show of thanks.

SEE ALSO

The Changes file for an explanation of how to view exhaustive details on what changed.

The INSTALL file for how to build Perl.

The README file for general stuff.

The Artistic and Copying files for copyright information.