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perl-5.41.3
⭐ Starred 2013 / Config::Perl::V
Security Advisories (8)
CVE-2024-56406 (2025-04-13)

A heap buffer overflow vulnerability was discovered in Perl. Release branches 5.34, 5.36, 5.38 and 5.40 are affected, including development versions from 5.33.1 through 5.41.10. When there are non-ASCII bytes in the left-hand-side of the `tr` operator, `S_do_trans_invmap` can overflow the destination pointer `d`.    $ perl -e '$_ = "\x{FF}" x 1000000; tr/\xFF/\x{100}/;'    Segmentation fault (core dumped) It is believed that this vulnerability can enable Denial of Service and possibly Code Execution attacks on platforms that lack sufficient defenses.

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 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-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-2026-13221 (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-2026-15534 (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-2026-19487 (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.

NAME

Config::Perl::V - Structured data retrieval of perl -V output

SYNOPSIS

use Config::Perl::V;

my $local_config = Config::Perl::V::myconfig ();
print $local_config->{config}{osname};

DESCRIPTION

$conf = myconfig ()

This function will collect the data described in "The hash structure" below, and return that as a hash reference. It optionally accepts an option to include more entries from %ENV. See "environment" below.

Note that this will not work on uninstalled perls when called with -I/path/to/uninstalled/perl/lib, but it works when that path is in $PERL5LIB or in $PERL5OPT, as paths passed using -I are not known when the -V information is collected.

$conf = plv2hash ($text [, ...])

Convert a sole 'perl -V' text block, or list of lines, to a complete myconfig hash. All unknown entries are defaulted.

$info = summary ([$conf])

Return an arbitrary selection of the information. If no $conf is given, myconfig () is used instead.

$md5 = signature ([$conf])

Return the MD5 of the info returned by summary () without the config_args entry.

If Digest::MD5 is not available, it return a string with only 0's.

The hash structure

The returned hash consists of 4 parts:

build

This information is extracted from the second block that is emitted by perl -V, and usually looks something like

 Characteristics of this binary (from libperl):
   Compile-time options: DEBUGGING USE_64_BIT_INT USE_LARGE_FILES
   Locally applied patches:
	 defined-or
	 MAINT24637
   Built under linux
   Compiled at Jun 13 2005 10:44:20
   @INC:
     /usr/lib/perl5/5.8.7/i686-linux-64int
     /usr/lib/perl5/5.8.7
     /usr/lib/perl5/site_perl/5.8.7/i686-linux-64int
     /usr/lib/perl5/site_perl/5.8.7
     /usr/lib/perl5/site_perl
     .

or

 Characteristics of this binary (from libperl):
   Compile-time options: DEBUGGING MULTIPLICITY
			 PERL_DONT_CREATE_GVSV PERL_IMPLICIT_CONTEXT
			 PERL_MALLOC_WRAP PERL_TRACK_MEMPOOL
			 PERL_USE_SAFE_PUTENV USE_ITHREADS
			 USE_LARGE_FILES USE_PERLIO
			 USE_REENTRANT_API
   Built under linux
   Compiled at Jan 28 2009 15:26:59

This information is not available anywhere else, including %Config, but it is the information that is only known to the perl binary.

The extracted information is stored in 5 entries in the build hash:

osname

This is most likely the same as $Config{osname}, and was the name known when perl was built. It might be different if perl was cross-compiled.

The default for this field, if it cannot be extracted, is to copy $Config{osname}. The two may be differing in casing (OpenBSD vs openbsd).

stamp

This is the time string for which the perl binary was compiled. The default value is 0.

options

This is a hash with all the known defines as keys. The value is either 0, which means unknown or unset, or 1, which means defined.

derived

As some variables are reported by a different name in the output of perl -V than their actual name in %Config, I decided to leave the config entry as close to reality as possible, and put in the entries that might have been guessed by the printed output in a separate block.

patches

This is a list of optionally locally applied patches. Default is an empty list.

environment

By default this hash is only filled with the environment variables out of %ENV that start with PERL, but you can pass the env option to myconfig to get more

my $conf = Config::Perl::V::myconfig ({ env => qr/^ORACLE/ });
my $conf = Config::Perl::V::myconfig ([ env => qr/^ORACLE/ ]);
config

This hash is filled with the variables that perl -V fills its report with, and it has the same variables that Config::myconfig returns from %Config.

inc

This is the list of default @INC.

REASONING

This module was written to be able to return the configuration for the currently used perl as deeply as needed for the CPANTESTERS framework. Up until now they used the output of myconfig as a single text blob, and so it was missing the vital binary characteristics of the running perl and the optional applied patches.

BUGS

Please feedback what is wrong

TODO

* Implement retrieval functions/methods
* Documentation
* Error checking
* Tests

AUTHOR

H.Merijn Brand <h.m.brand@xs4all.nl>

COPYRIGHT AND LICENSE

Copyright (C) 2009-2023 H.Merijn Brand

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