/ 
perl-5.44.0
⭐ Starred 2013 / utf8::all
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

utf8::all - turn on Unicode - all of it

VERSION

version 0.010

SYNOPSIS

use utf8::all; # Turn on UTF-8. All of it.

open my $in, '<', 'contains-utf8';  # UTF-8 already turned on here
print length 'føø bār';             # 7 UTF-8 characters
my $utf8_arg = shift @ARGV;         # @ARGV is UTF-8 too!

DESCRIPTION

utf8 allows you to write your Perl encoded in UTF-8. That means UTF-8 strings, variable names, and regular expressions. utf8::all goes further, and makes @ARGV encoded in UTF-8, and filehandles are opened with UTF-8 encoding turned on by default (including STDIN, STDOUT, STDERR), and charnames are imported so \N{...} sequences can be used to compile Unicode characters based on names. If you don't want UTF-8 for a particular filehandle, you'll have to set binmode $filehandle.

The pragma is lexically-scoped, so you can do the following if you had some reason to:

{
    use utf8::all;
    open my $out, '>', 'outfile';
    my $utf8_str = 'føø bār';
    print length $utf8_str, "\n"; # 7
    print $out $utf8_str;         # out as utf8
}
open my $in, '<', 'outfile';      # in as raw
my $text = do { local $/; <$in>};
print length $text, "\n";         # 10, not 7!

INTERACTION WITH AUTODIE

If you use autodie, which is a great idea, you need to use at least version 2.12, released on June 26, 2012. Otherwise, autodie obliterates the IO layers set by the open pragma. See RT #54777 and GH #7.

AVAILABILITY

The project homepage is http://metacpan.org/release/utf8-all/.

The latest version of this module is available from the Comprehensive Perl Archive Network (CPAN). Visit http://www.perl.com/CPAN/ to find a CPAN site near you, or see https://metacpan.org/module/utf8::all/.

SOURCE

The development version is on github at http://github.com/doherty/utf8-all and may be cloned from git://github.com/doherty/utf8-all.git

BUGS AND LIMITATIONS

You can make new bug reports, and view existing ones, through the web interface at https://github.com/doherty/utf8-all/issues.

AUTHORS

  • Michael Schwern <mschwern@cpan.org>

  • Mike Doherty <doherty@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2009 by Michael Schwern <mschwern@cpan.org>.

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