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perl-5.43.8
⭐ Starred 2013 / deprecate
Security Advisories (4)
CVE-2026-57432 (2026-07-13)

Perl versions through 5.43.10 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 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-2026-13221 (2026-07-13)

Perl versions through 5.43.9 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-2026-4176 (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

deprecate - Perl pragma for deprecating the inclusion of a module in core

SYNOPSIS

use deprecate;  # warn about future absence if loaded from core

DESCRIPTION

This pragma simplifies the maintenance of dual-life modules that will no longer be included in the Perl core in a future Perl release, but are still included currently.

The purpose of the pragma is to alert users to the status of such a module by issuing a warning that encourages them to install the module from CPAN, so that a future upgrade to a perl which omits the module will not break their code.

This warning will only be issued if the module was loaded from a core library directory, which allows the use deprecate line to be included in the CPAN version of the module. Because the pragma remains silent when the module is run from a non-core library directory, the pragma call does not need to be patched into or out of either the core or CPAN version of the module. The exact same code can be shipped for either purpose.

Important Caveat

Note that when a module installs from CPAN to a core library directory rather than the site library directories, the user gains no protection from having installed it.

At the same time, this pragma cannot detect when such a module has installed from CPAN to the core library, and so it would endlessly and uselessly exhort the user to upgrade.

Therefore modules that can install from CPAN to the core library must make sure not to call this pragma when they have done so. Generally this means that the exact logic from the installer must be mirrored inside the module. E.g.:

# Makefile.PL
WriteMakefile(
    # ...
    INSTALLDIRS => ( "$]" >= 5.011 ? 'site' : 'perl' ),
);

# lib/Foo/Bar.pm
use if "$]" >= 5.011, 'deprecate';

(The above example shows the most important case of this: when the target is a Perl older than 5.12 (where the core library directories take precedence over the site library directories) and the module being installed was included in core in that Perl version. Under those circumstances, an upgrade of the module from CPAN is only possible by installing to the core library.)

EXPORT

None by default. The only method is import, called by use deprecate;.

SEE ALSO

First example to use deprecate; was Switch.

AUTHOR

Original version by Nicholas Clark

COPYRIGHT AND LICENSE

Copyright (C) 2009, 2011

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.10.0 or, at your option, any later version of Perl 5 you may have available.