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perl-5.26.2
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Security Advisories (12)
CVE-2020-12723 (2020-06-05)

regcomp.c in Perl before 5.30.3 allows a buffer overflow via a crafted regular expression because of recursive S_study_chunk calls.

CVE-2020-10878 (2020-06-05)

Perl before 5.30.3 has an integer overflow related to mishandling of a "PL_regkind[OP(n)] == NOTHING" situation. A crafted regular expression could lead to malformed bytecode with a possibility of instruction injection.

CVE-2020-10543 (2020-06-05)

Perl before 5.30.3 on 32-bit platforms allows a heap-based buffer overflow because nested regular expression quantifiers have an integer overflow.

CVE-2018-6798 (2018-04-17)

An issue was discovered in Perl 5.22 through 5.26. Matching a crafted locale dependent regular expression can cause a heap-based buffer over-read and potentially information disclosure.

CVE-2018-18314 (2018-12-07)

Perl before 5.26.3 has a buffer overflow via a crafted regular expression that triggers invalid write operations.

CVE-2018-18313 (2018-12-07)

Perl before 5.26.3 has a buffer over-read via a crafted regular expression that triggers disclosure of sensitive information from process memory.

CVE-2018-18312 (2018-12-05)

Perl before 5.26.3 and 5.28.0 before 5.28.1 has a buffer overflow via a crafted regular expression that triggers invalid write operations.

CVE-2018-18311 (2018-12-07)

Perl before 5.26.3 and 5.28.x before 5.28.1 has a buffer overflow via a crafted regular expression that triggers invalid write operations.

CVE-2023-47039 (2023-10-30)

Perl for Windows relies on the system path environment variable to find the shell (cmd.exe). When running an executable which uses Windows Perl interpreter, Perl attempts to find and execute cmd.exe within the operating system. However, due to path search order issues, Perl initially looks for cmd.exe in the current working directory. An attacker with limited privileges can exploit this behavior by placing cmd.exe in locations with weak permissions, such as C:\ProgramData. By doing so, when an administrator attempts to use this executable from these compromised locations, arbitrary code can be executed.

CVE-2023-47100

In Perl before 5.38.2, S_parse_uniprop_string in regcomp.c can write to unallocated space because a property name associated with a \p{...} regular expression construct is mishandled. The earliest affected version is 5.30.0.

CVE-2024-56406 (2025-04-13)

A heap buffer overflow vulnerability was discovered in Perl. 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

NAME

perldelta - what is new for perl v5.26.2

DESCRIPTION

This document describes differences between the 5.26.1 release and the 5.26.2 release.

If you are upgrading from an earlier release such as 5.26.0, first read perl5261delta, which describes differences between 5.26.0 and 5.26.1.

Security

[CVE-2018-6797] heap-buffer-overflow (WRITE of size 1) in S_regatom (regcomp.c)

A crafted regular expression could cause a heap buffer write overflow, with control over the bytes written. [perl #132227]

[CVE-2018-6798] Heap-buffer-overflow in Perl__byte_dump_string (utf8.c)

Matching a crafted locale dependent regular expression could cause a heap buffer read overflow and potentially information disclosure. [perl #132063]

[CVE-2018-6913] heap-buffer-overflow in S_pack_rec

pack() could cause a heap buffer write overflow with a large item count. [perl #131844]

Assertion failure in Perl__core_swash_init (utf8.c)

Control characters in a supposed Unicode property name could cause perl to crash. This has been fixed. [perl #132055] [perl #132553] [perl #132658]

Incompatible Changes

There are no changes intentionally incompatible with 5.26.1. If any exist, they are bugs, and we request that you submit a report. See "Reporting Bugs" below.

Modules and Pragmata

Updated Modules and Pragmata

Documentation

Changes to Existing Documentation

perluniprops

  • This has been updated to note that \p{Word} now includes code points matching the \p{Join_Control} property. The change to the property was made in Perl 5.18, but not documented until now. There are currently only two code points that match this property: U+200C (ZERO WIDTH NON-JOINER) and U+200D (ZERO WIDTH JOINER).

Platform Support

Platform-Specific Notes

Windows

Visual C++ compiler version detection has been improved to work on non-English language systems. [perl #132421]

We now set $Config{libpth} correctly for 64-bit builds using Visual C++ versions earlier than 14.1. [perl #132484]

Selected Bug Fixes

  • The readpipe() built-in function now checks at compile time that it has only one parameter expression, and puts it in scalar context, thus ensuring that it doesn't corrupt the stack at runtime. [perl #4574]

  • Fixed a use after free bug in pp_list introduced in Perl 5.27.1. [perl #131954]

  • Parsing a sub definition could cause a use after free if the sub keyword was followed by whitespace including newlines (and comments). [perl #131836]

  • The tokenizer now correctly adjusts a parse pointer when skipping whitespace in an ${identifier} construct. [perl #131949]

  • Accesses to ${^LAST_FH} no longer assert after using any of a variety of I/O operations on a non-glob. [perl #128263]

  • sort now performs correct reference counting when aliasing $a and $b, thus avoiding premature destruction and leakage of scalars if they are re-aliased during execution of the sort comparator. [perl #92264]

  • Some convoluted kinds of regexp no longer cause an arithmetic overflow when compiled. [perl #131893]

  • Fixed a duplicate symbol failure with -flto -mieee-fp builds. pp.c defined _LIB_VERSION which -lieee already defines. [perl #131786]

  • A NULL pointer dereference in the S_regmatch() function has been fixed. [perl #132017]

  • Failures while compiling code within other constructs, such as with string interpolation and the right part of s///e now cause compilation to abort earlier.

    Previously compilation could continue in order to report other errors, but the failed sub-parse could leave partly parsed constructs on the parser shift-reduce stack, confusing the parser, leading to perl crashes. [perl #125351]

Acknowledgements

Perl 5.26.2 represents approximately 7 months of development since Perl 5.26.1 and contains approximately 3,300 lines of changes across 82 files from 17 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 1,800 lines of changes to 36 .pm, .t, .c and .h files.

Perl continues to flourish into its third decade thanks to a vibrant community of users and developers. The following people are known to have contributed the improvements that became Perl 5.26.2:

Aaron Crane, Abigail, Chris 'BinGOs' Williams, H.Merijn Brand, James E Keenan, Jarkko Hietaniemi, John SJ Anderson, Karen Etheridge, Karl Williamson, Lukas Mai, Renee Baecker, Sawyer X, Steve Hay, Todd Rinaldo, Tony Cook, Yves Orton, Zefram.

The list above is almost certainly incomplete as it is automatically generated from version control history. In particular, it does not include the names of the (very much appreciated) contributors who reported issues to the Perl bug tracker.

Many of the changes included in this version originated in the CPAN modules included in Perl's core. We're grateful to the entire CPAN community for helping Perl to flourish.

For a more complete list of all of Perl's historical contributors, please see the AUTHORS file in the Perl source distribution.

Reporting Bugs

If you find what you think is a bug, you might check the perl bug database at https://rt.perl.org/ . There may also be information at http://www.perl.org/ , the Perl Home Page.

If you believe you have an unreported bug, please run the perlbug program included with your release. Be sure to trim your bug down to a tiny but sufficient test case. Your bug report, along with the output of perl -V, will be sent off to perlbug@perl.org to be analysed by the Perl porting team.

If the bug you are reporting has security implications which make it inappropriate to send to a publicly archived mailing list, then see "SECURITY VULNERABILITY CONTACT INFORMATION" in perlsec for details of how to report the issue.

Give Thanks

If you wish to thank the Perl 5 Porters for the work we had done in Perl 5, you can do so by running the perlthanks program:

perlthanks

This will send an email to the Perl 5 Porters list with your show of thanks.

SEE ALSO

The Changes file for an explanation of how to view exhaustive details on what changed.

The INSTALL file for how to build Perl.

The README file for general stuff.

The Artistic and Copying files for copyright information.