Security Advisories (7)
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-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-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-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

perl5124delta - what is new for perl v5.12.4

DESCRIPTION

This document describes differences between the 5.12.3 release and the 5.12.4 release.

If you are upgrading from an earlier release such as 5.12.2, first read perl5123delta, which describes differences between 5.12.2 and 5.12.3. The major changes made in 5.12.0 are described in perl5120delta.

Incompatible Changes

There are no changes intentionally incompatible with 5.12.3. If any exist, they are bugs and reports are welcome.

Selected Bug Fixes

When strict "refs" mode is off, %{...} in rvalue context returns undef if its argument is undefined. An optimisation introduced in Perl 5.12.0 to make keys %{...} faster when used as a boolean did not take this into account, causing keys %{+undef} (and keys %$foo when $foo is undefined) to be an error, which it should be so in strict mode only [perl #81750].

lc, uc, lcfirst, and ucfirst no longer return untainted strings when the argument is tainted. This has been broken since perl 5.8.9 [perl #87336].

Fixed a case where it was possible that a freed buffer may have been read from when parsing a here document.

Modules and Pragmata

Module::CoreList has been upgraded from version 2.43 to 2.50.

Testing

The cpan/CGI/t/http.t test script has been fixed to work when the environment has HTTPS_* environment variables, such as HTTPS_PROXY.

Documentation

Updated the documentation for rand() in perlfunc to note that it is not cryptographically secure.

Platform Specific Notes

Linux

Support Ubuntu 11.04's new multi-arch library layout.

Acknowledgements

Perl 5.12.4 represents approximately 5 months of development since Perl 5.12.3 and contains approximately 200 lines of changes across 11 files from 8 authors.

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 5.12.4:

Andy Dougherty, David Golden, David Leadbeater, Father Chrysostomos, Florian Ragwitz, Jesse Vincent, Leon Brocard, Zsbán Ambrus.

Reporting Bugs

If you find what you think is a bug, you might check the articles recently posted to the comp.lang.perl.misc newsgroup and the perl bug database at http://rt.perl.org/perlbug/ . 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 please send it to perl5-security-report@perl.org. This points to a closed subscription unarchived mailing list, which includes all the core committers, who be able to help assess the impact of issues, figure out a resolution, and help co-ordinate the release of patches to mitigate or fix the problem across all platforms on which Perl is supported. Please only use this address for security issues in the Perl core, not for modules independently distributed on CPAN.

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.