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perl-5.45.1
⭐ Starred 2013 / perl5404delta
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

perl5404delta - what is new for perl v5.40.4

DESCRIPTION

This document describes differences between the 5.40.3 release and the 5.40.4 release.

If you are upgrading from an earlier release such as 5.40.2, first read perl5403delta, which describes differences between 5.40.2 and 5.40.3.

Security

[CVE-2026-4176] Vulnerability in Compress::Raw::Zlib

Compress::Raw::Zlib is included in Perl as a dual-life core module, and was vulnerable to [CVE-2026-3381] due to a vendored version of zlib which had several vulnerabilities, including [CVE-2026-27171].

This problem was assigned [CVE-2026-4176] by the CPAN Security Group.

Incompatible Changes

There are no changes intentionally incompatible with 5.40.3. If any exist, they are bugs, and we request that you submit a report. See "Reporting Bugs" below.

Modules and Pragmata

Updated Modules and Pragmata

Documentation

Changes to Existing Documentation

We have attempted to update the documentation to reflect the changes listed in this document. If you find any we have missed, open an issue at https://github.com/Perl/perl5/issues.

Testing

Tests were added and changed to reflect the other additions and changes in this release.

Acknowledgements

Perl 5.40.4 represents approximately 8 months of development since Perl 5.40.3 and contains approximately 4,000 lines of changes across 58 files from 10 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 2,800 lines of changes to 24 .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 5.40.4:

Eric Herman, James E Keenan, Karen Etheridge, Max Maischein, Olaf Alders, Paul Marquess, Philippe Bruhat (BooK), Richard Leach, Steve Hay, Thibault Duponchelle.

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.