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perl-5.21.2
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Security Advisories (19)
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-2018-6797 (2018-04-17)

An issue was discovered in Perl 5.18 through 5.26. A crafted regular expression can cause a heap-based buffer overflow, with control over the bytes written.

CVE-2018-6913 (2018-04-17)

Heap-based buffer overflow in the pack function in Perl before 5.26.2 allows context-dependent attackers to execute arbitrary code via a large item count.

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-2017-12883 (2017-09-19)

Buffer overflow in the S_grok_bslash_N function in regcomp.c in Perl 5 before 5.24.3-RC1 and 5.26.x before 5.26.1-RC1 allows remote attackers to disclose sensitive information or cause a denial of service (application crash) via a crafted regular expression with an invalid '\\N{U+...}' escape.

CVE-2017-12837 (2017-09-19)

Heap-based buffer overflow in the S_regatom function in regcomp.c in Perl 5 before 5.24.3-RC1 and 5.26.x before 5.26.1-RC1 allows remote attackers to cause a denial of service (out-of-bounds write) via a regular expression with a '\\N{}' escape and the case-insensitive modifier.

CVE-2015-8853 (2016-05-25)

The (1) S_reghop3, (2) S_reghop4, and (3) S_reghopmaybe3 functions in regexec.c in Perl before 5.24.0 allow context-dependent attackers to cause a denial of service (infinite loop) via crafted utf-8 data, as demonstrated by "a\x80."

CVE-2016-2381 (2016-04-08)

Perl might allow context-dependent attackers to bypass the taint protection mechanism in a child process via duplicate environment variables in envp.

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

CVE-2016-1238 (2016-08-02)

(1) cpan/Archive-Tar/bin/ptar, (2) cpan/Archive-Tar/bin/ptardiff, (3) cpan/Archive-Tar/bin/ptargrep, (4) cpan/CPAN/scripts/cpan, (5) cpan/Digest-SHA/shasum, (6) cpan/Encode/bin/enc2xs, (7) cpan/Encode/bin/encguess, (8) cpan/Encode/bin/piconv, (9) cpan/Encode/bin/ucmlint, (10) cpan/Encode/bin/unidump, (11) cpan/ExtUtils-MakeMaker/bin/instmodsh, (12) cpan/IO-Compress/bin/zipdetails, (13) cpan/JSON-PP/bin/json_pp, (14) cpan/Test-Harness/bin/prove, (15) dist/ExtUtils-ParseXS/lib/ExtUtils/xsubpp, (16) dist/Module-CoreList/corelist, (17) ext/Pod-Html/bin/pod2html, (18) utils/c2ph.PL, (19) utils/h2ph.PL, (20) utils/h2xs.PL, (21) utils/libnetcfg.PL, (22) utils/perlbug.PL, (23) utils/perldoc.PL, (24) utils/perlivp.PL, and (25) utils/splain.PL in Perl 5.x before 5.22.3-RC2 and 5.24 before 5.24.1-RC2 do not properly remove . (period) characters from the end of the includes directory array, which might allow local users to gain privileges via a Trojan horse module under the current working directory.

CVE-2015-8608 (2017-02-07)

The VDir::MapPathA and VDir::MapPathW functions in Perl 5.22 allow remote attackers to cause a denial of service (out-of-bounds read) and possibly execute arbitrary code via a crafted (1) drive letter or (2) pInName argument.

NAME

perldelta - what is new for perl v5.21.2

DESCRIPTION

This document describes differences between the 5.21.1 release and the 5.21.2 release.

If you are upgrading from an earlier release such as 5.21.0, first read perl5211delta, which describes differences between 5.21.0 and 5.21.1.

Core Enhancements

Better heuristics on older platforms for determining locale UTF8ness

On platforms that implement neither the C99 standard nor the POSIX 2001 standard, determining if the current locale is UTF8 or not depends on heuristics. These are improved in this release.

Security

Perl is now always compiled with -D_FORTIFY_SOURCE=2 if available

The 'code hardening' option called _FORTIFY_SOURCE, available in gcc 4.*, is now always used for compiling Perl, if available.

Note that this isn't necessarily a huge step since in many platforms the step had already been taken several years ago: many Linux distributions (like Fedora) have been using this option for Perl, and OS X has enforced the same for many years.

Deprecations

/\C/ character class

This character class, which matches a single byte, even if it appears in a multi-byte character has been deprecated. Matching single bytes in a multi-byte character breaks encapsulation, and can corrupt utf8 strings.

Performance Enhancements

  • Refactoring of pp_tied and Cpp_ref for small improvements.

  • Pathtools don't try to load XS on miniperl.

  • A typo fix reduces the size of the OP structure.

  • Hash lookups where the key is a constant is faster.

Modules and Pragmata

Updated Modules and Pragmata

  • arybase has been upgraded from version 0.07 to 0.08.

  • B has been upgraded from version 1.49 to 1.50.

  • Devel::Peek has been upgraded from version 1.17 to 1.18.

  • experimental has been upgraded from version 0.007 to 0.008.

  • ExtUtils::Manifest has been upgraded from version 1.63 to 1.64.

  • File::Copy has been upgraded from version 2.29 to 2.30.

  • The PathTools module collection (File::Spec and friends) has been upgraded from version 3.48 to 3.49.

  • Filter::Simple has been upgraded from version 0.91 to 0.92.

  • Hash::Util has been upgraded from version 0.17 to 0.18.

  • IO has been upgraded from version 1.32 to 1.33.

  • IO::Socket::IP has been upgraded from version 0.29 to 0.31.

    A better fix for subclassing connect(). [cpan #95983] [cpan #97050]

  • IPC::Open3 has been upgraded from version 1.16 to 1.17.

  • Math::BigInt has been upgraded from version 1.9995 to 1.9996.

    Correct handling of subclasses. [cpan #96254] [cpan #96329]

  • Module::CoreList has been upgraded from version 5.021001_01 to 5.021002.

  • Pod::Usage has been upgraded from version 1.63 to 1.64.

  • POSIX has been upgraded from version 1.40 to 1.41.

  • threads has been upgraded from version 1.94 to 1.95.

  • warnings has been upgraded from version 1.24 to 1.26.

Documentation

Changes to Existing Documentation

perlpolicy

perlfunc

  • Improve documentation of our.

perlsyn

  • The empty conditional in for and while is now documented in perlsyn.

Diagnostics

New Diagnostics

New Warnings

Configuration and Compilation

  • A new compilation flag, -DPERL_OP_PARENT is available. For details, see the discussion below at "Internal Changes".

Testing

  • test.pl now allows plan skip_all => $reason, to make it more compatible with Test::More.

Platform Support

Platform-Specific Notes

Solaris

Builds on Solaris 10 with -Dusedtrace would fail early since make didn't follow implied dependencies to build perldtrace.h. Added an explicit dependency to depend. [perl #120120]

Internal Changes

  • The following private API functions had their context parameter removed, Perl_cast_ulong, Perl_cast_i32, Perl_cast_iv, Perl_cast_uv, Perl_cv_const_sv, Perl_mg_find, Perl_mg_findext, Perl_mg_magical, Perl_mini_mktime, Perl_my_dirfd, Perl_sv_backoff, Perl_utf8_hop.

    Users of the public API prefix-less calls remain unaffected.

  • Experimental support for ops in the optree to be able to locate their parent, if any. A general-purpose function, op_sibling_splice() allows for general manipulating an op_sibling chain. The last op in such a chain is now marked with the field op_lastsib.

    A new build define, -DPERL_OP_PARENT has been added; if given, it forces the core to use op_lastsib to detect the last sibling in a chain, freeing the last op_sibling pointer, which then points back to the parent (instead of being NULL).

    A C-level op_parent() function, and a B parent() method have been added; under a default build, they return NULL, but when -DPERL_OP_PARENT has been set, they return the parent of the current op.

Selected Bug Fixes

  • s///e on tainted utf8 strings got pos() messed up. This bug, introduced in 5.20, is now fixed. [RT #122148]

  • A non-word boundary in a regular expression (\B) did not always match the end of the string; in particular q{} =~ /\B/ did not match. This bug, introduced in perl 5.14, is now fixed. [RT #122090]

  • " P" =~ /(?=.*P)P/ should match, but did not. This is now fixed. [RT #122171].

Acknowledgements

Perl 5.21.2 represents approximately 4 weeks of development since Perl 5.21.1 and contains approximately 11,000 lines of changes across 220 files from 27 authors.

Excluding auto-generated files, documentation and release tools, there were approximately 5,700 lines of changes to 140 .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 5.21.2:

Aaron Crane, Abhijit Menon-Sen, Abigail, Alexandr Ciornii, brian d foy, Brian Fraser, Chris 'BinGOs' Williams, Craig A. Berry, Daniel Dragan, David Golden, David Mitchell, Dmitri Tikhonov, George Greer, H.Merijn Brand, James E Keenan, Jarkko Hietaniemi, Karen Etheridge, Karl Williamson, Matthew Horsfall, Peter John Acklam, Peter Martini, Reini Urban, Ricardo Signes, Steve Hay, Tony Cook, Yves Orton, Ævar Arnfjörð Bjarmason.

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 articles recently posted to the comp.lang.perl.misc newsgroup and 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 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 will 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.