/ 
perl-5.42.0
⭐ Starred 2013 / Parse::CPAN::Meta
Security Advisories (5)
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-2026-57432 (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-2026-15534 (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.

NAME

Parse::CPAN::Meta - Parse META.yml and META.json CPAN metadata files

VERSION

version 2.150010

SYNOPSIS

#############################################
# In your file

---
name: My-Distribution
version: 1.23
resources:
  homepage: "http://example.com/dist/My-Distribution"


#############################################
# In your program

use Parse::CPAN::Meta;

my $distmeta = Parse::CPAN::Meta->load_file('META.yml');

# Reading properties
my $name     = $distmeta->{name};
my $version  = $distmeta->{version};
my $homepage = $distmeta->{resources}{homepage};

DESCRIPTION

Parse::CPAN::Meta is a parser for META.json and META.yml files, using JSON::PP and/or CPAN::Meta::YAML.

Parse::CPAN::Meta provides three methods: load_file, load_json_string, and load_yaml_string. These will read and deserialize CPAN metafiles, and are described below in detail.

Parse::CPAN::Meta provides a legacy API of only two functions, based on the YAML functions of the same name. Wherever possible, identical calling semantics are used. These may only be used with YAML sources.

All error reporting is done with exceptions (die'ing).

Note that META files are expected to be in UTF-8 encoding, only. When converted string data, it must first be decoded from UTF-8.

METHODS

load_file

my $metadata_structure = Parse::CPAN::Meta->load_file('META.json');

my $metadata_structure = Parse::CPAN::Meta->load_file('META.yml');

This method will read the named file and deserialize it to a data structure, determining whether it should be JSON or YAML based on the filename. The file will be read using the ":utf8" IO layer.

load_yaml_string

my $metadata_structure = Parse::CPAN::Meta->load_yaml_string($yaml_string);

This method deserializes the given string of YAML and returns the first document in it. (CPAN metadata files should always have only one document.) If the source was UTF-8 encoded, the string must be decoded before calling load_yaml_string.

load_json_string

my $metadata_structure = Parse::CPAN::Meta->load_json_string($json_string);

This method deserializes the given string of JSON and the result. If the source was UTF-8 encoded, the string must be decoded before calling load_json_string.

load_string

my $metadata_structure = Parse::CPAN::Meta->load_string($some_string);

If you don't know whether a string contains YAML or JSON data, this method will use some heuristics and guess. If it can't tell, it assumes YAML.

yaml_backend

my $backend = Parse::CPAN::Meta->yaml_backend;

Returns the module name of the YAML serializer. See "ENVIRONMENT" for details.

json_backend

my $backend = Parse::CPAN::Meta->json_backend;

Returns the module name of the JSON serializer. If CPAN_META_JSON_BACKEND is set, this will be whatever that's set to. If not, this will either be JSON::PP or JSON. If PERL_JSON_BACKEND is set, this will return JSON as further delegation is handled by the JSON module. See "ENVIRONMENT" for details.

json_decoder

my $decoder = Parse::CPAN::Meta->json_decoder;

Returns the module name of the JSON decoder. Unlike "json_backend", this is not necessarily a full JSON-style module, but only something that will provide a decode_json subroutine. If CPAN_META_JSON_DECODER is set, this will be whatever that's set to. If not, this will be whatever has been selected as "json_backend". See "ENVIRONMENT" for more notes.

FUNCTIONS

For maintenance clarity, no functions are exported by default. These functions are available for backwards compatibility only and are best avoided in favor of load_file.

Load

my @yaml = Parse::CPAN::Meta::Load( $string );

Parses a string containing a valid YAML stream into a list of Perl data structures.

LoadFile

my @yaml = Parse::CPAN::Meta::LoadFile( 'META.yml' );

Reads the YAML stream from a file instead of a string.

ENVIRONMENT

CPAN_META_JSON_DECODER

By default, JSON::PP will be used for deserializing JSON data. If the CPAN_META_JSON_DECODER environment variable exists, this is expected to be the name of a loadable module that provides a decode_json subroutine, which will then be used for deserialization. Relying only on the existence of said subroutine allows for maximum compatibility, since this API is provided by all of JSON::PP, JSON::XS, Cpanel::JSON::XS, JSON::MaybeXS, JSON::Tiny, and Mojo::JSON.

CPAN_META_JSON_BACKEND

By default, JSON::PP will be used for deserializing JSON data. If the CPAN_META_JSON_BACKEND environment variable exists, this is expected to be the name of a loadable module that provides the JSON API, since downstream code expects to be able to call new on this class. As such, while JSON::PP, JSON::XS, Cpanel::JSON::XS and JSON::MaybeXS will work for this, to use Mojo::JSON or JSON::Tiny for decoding requires setting "CPAN_META_JSON_DECODER".

PERL_JSON_BACKEND

If the CPAN_META_JSON_BACKEND environment variable does not exist, and if PERL_JSON_BACKEND environment variable exists, is true and is not "JSON::PP", then the JSON module (version 2.5 or greater) will be loaded and used to interpret PERL_JSON_BACKEND. If JSON is not installed or is too old, an exception will be thrown. Note that at the time of writing, the only useful values are 1, which will tell JSON to guess, or JSON::XS - if you want to use a newer JSON module, see "CPAN_META_JSON_BACKEND".

PERL_YAML_BACKEND

By default, CPAN::Meta::YAML will be used for deserializing YAML data. If the PERL_YAML_BACKEND environment variable is defined, then it is interpreted as a module to use for deserialization. The given module must be installed, must load correctly and must implement the Load() function or an exception will be thrown.

AUTHORS

  • David Golden <dagolden@cpan.org>

  • Ricardo Signes <rjbs@cpan.org>

  • Adam Kennedy <adamk@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2010 by David Golden, Ricardo Signes, Adam Kennedy and Contributors.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.