/ 
perl-5.44.0
⭐ Starred 2013 / CPAN::Meta::YAML
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

CPAN::Meta::YAML - Read and write a subset of YAML for CPAN Meta files

VERSION

version 0.020

SYNOPSIS

use CPAN::Meta::YAML;

# reading a META file
open $fh, "<:utf8", "META.yml";
$yaml_text = do { local $/; <$fh> };
$yaml = CPAN::Meta::YAML->read_string($yaml_text)
  or die CPAN::Meta::YAML->errstr;

# finding the metadata
$meta = $yaml->[0];

# writing a META file
$yaml_text = $yaml->write_string
  or die CPAN::Meta::YAML->errstr;
open $fh, ">:utf8", "META.yml";
print $fh $yaml_text;

DESCRIPTION

This module implements a subset of the YAML specification for use in reading and writing CPAN metadata files like META.yml and MYMETA.yml. It should not be used for any other general YAML parsing or generation task.

NOTE: META.yml (and MYMETA.yml) files should be UTF-8 encoded. Users are responsible for proper encoding and decoding. In particular, the read and write methods do not support UTF-8 and should not be used.

SUPPORT

This module is currently derived from YAML::Tiny by Adam Kennedy. If there are bugs in how it parses a particular META.yml file, please file a bug report in the YAML::Tiny bugtracker: https://github.com/Perl-Toolchain-Gang/YAML-Tiny/issues

SEE ALSO

YAML::Tiny, YAML, YAML::XS

AUTHORS

  • Adam Kennedy <adamk@cpan.org>

  • David Golden <dagolden@cpan.org>

CONTRIBUTOR

Karen Etheridge <ether@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2010 by Adam Kennedy.

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