Security Advisories (6)
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-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-2026-57432 (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

Pod::Text::Overstrike - Convert POD data to formatted overstrike text

SYNOPSIS

use Pod::Text::Overstrike;
my $parser = Pod::Text::Overstrike->new (sentence => 0, width => 78);

# Read POD from STDIN and write to STDOUT.
$parser->parse_from_filehandle;

# Read POD from file.pod and write to file.txt.
$parser->parse_from_file ('file.pod', 'file.txt');

DESCRIPTION

Pod::Text::Overstrike is a simple subclass of Pod::Text that highlights output text using overstrike sequences, in a manner similar to nroff. Characters in bold text are overstruck (character, backspace, character) and characters in underlined text are converted to overstruck underscores (underscore, backspace, character). This format was originally designed for hard-copy terminals and/or line printers, yet is readable on soft-copy (CRT) terminals.

Overstruck text is best viewed by page-at-a-time programs that take advantage of the terminal's stand-out and underline capabilities, such as the less program on Unix.

Apart from the overstrike, it in all ways functions like Pod::Text. See Pod::Text for details and available options.

BUGS

Currently, the outermost formatting instruction wins, so for example underlined text inside a region of bold text is displayed as simply bold. There may be some better approach possible.

COMPATIBILITY

Pod::Text::Overstrike 1.01 (based on Pod::Parser) was the first version of this module included with Perl, in Perl 5.6.1.

The current API based on Pod::Simple was added in Pod::Text::Overstrike 2.00, included in Perl 5.9.3.

Several problems with wrapping and line length were fixed as recently as Pod::Text::Overstrike 6.0.0.

This module inherits its API and most behavior from Pod::Text, so the details in "COMPATIBILITY" in Pod::Text also apply. Pod::Text and Pod::Text::Overstrike have had the same module version since 4.00, included in Perl 5.23.7. (They unfortunately diverge in confusing ways prior to that.)

CAVEATS

Line wrapping is done only at ASCII spaces and tabs, rather than using a correct Unicode-aware line wrapping algorithm.

AUTHOR

Originally written by Joe Smith <Joe.Smith@inwap.com>, using the framework created by Russ Allbery <rra@cpan.org>. Subsequently updated by Russ Allbery.

COPYRIGHT AND LICENSE

Copyright 2000 Joe Smith <Joe.Smith@inwap.com>

Copyright 2001, 2004, 2008, 2014, 2018-2019, 2022, 2024 Russ Allbery <rra@cpan.org>

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

SEE ALSO

Pod::Text, Pod::Simple

The current version of this module is always available from its web site at https://www.eyrie.org/~eagle/software/podlators/. It is also part of the Perl core distribution as of 5.6.0.