/ 
perl-5.34.0-RC2
⭐ Starred 2013
/ cpan
Security Advisories (6)
CVE-2022-48522 (2023-08-22)

In Perl 5.34.0, function S_find_uninit_var in sv.c has a stack-based crash that can lead to remote code execution or local privilege escalation.

CVE-2023-47038 (2023-10-30)

A crafted regular expression when compiled by perl 5.30.0 through 5.38.0 can cause a one attacker controlled byte buffer overflow in a heap allocated buffer

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-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.

NAME

cpan - easily interact with CPAN from the command line

SYNOPSIS

# with arguments and no switches, installs specified modules
cpan module_name [ module_name ... ]

# with switches, installs modules with extra behavior
cpan [-cfFimtTw] module_name [ module_name ... ]

# use local::lib
cpan -I module_name [ module_name ... ]

# one time mirror override for faster mirrors
cpan -p ...

# with just the dot, install from the distribution in the
# current directory
cpan .

# without arguments, starts CPAN.pm shell
cpan

# without arguments, but some switches
cpan [-ahpruvACDLOPX]

DESCRIPTION

This script provides a command interface (not a shell) to CPAN. At the moment it uses CPAN.pm to do the work, but it is not a one-shot command runner for CPAN.pm.

Options

-a

Creates a CPAN.pm autobundle with CPAN::Shell->autobundle.

-A module [ module ... ]

Shows the primary maintainers for the specified modules.

-c module

Runs a `make clean` in the specified module's directories.

-C module [ module ... ]

Show the Changes files for the specified modules

-D module [ module ... ]

Show the module details. This prints one line for each out-of-date module (meaning, modules locally installed but have newer versions on CPAN). Each line has three columns: module name, local version, and CPAN version.

-f

Force the specified action, when it normally would have failed. Use this to install a module even if its tests fail. When you use this option, -i is not optional for installing a module when you need to force it:

% cpan -f -i Module::Foo
-F

Turn off CPAN.pm's attempts to lock anything. You should be careful with this since you might end up with multiple scripts trying to muck in the same directory. This isn't so much of a concern if you're loading a special config with -j, and that config sets up its own work directories.

-g module [ module ... ]

Downloads to the current directory the latest distribution of the module.

-G module [ module ... ]

UNIMPLEMENTED

Download to the current directory the latest distribution of the modules, unpack each distribution, and create a git repository for each distribution.

If you want this feature, check out Yanick Champoux's Git::CPAN::Patch distribution.

-h

Print a help message and exit. When you specify -h, it ignores all of the other options and arguments.

-i module [ module ... ]

Install the specified modules. With no other switches, this switch is implied.

-I

Load local::lib (think like -I for loading lib paths). Too bad -l was already taken.

-j Config.pm

Load the file that has the CPAN configuration data. This should have the same format as the standard CPAN/Config.pm file, which defines $CPAN::Config as an anonymous hash.

-J

Dump the configuration in the same format that CPAN.pm uses. This is useful for checking the configuration as well as using the dump as a starting point for a new, custom configuration.

-l

List all installed modules with their versions

-L author [ author ... ]

List the modules by the specified authors.

-m

Make the specified modules.

-M mirror1,mirror2,...

A comma-separated list of mirrors to use for just this run. The -P option can find them for you automatically.

-n

Do a dry run, but don't actually install anything. (unimplemented)

-O

Show the out-of-date modules.

-p

Ping the configured mirrors and print a report

-P

Find the best mirrors you could be using and use them for the current session.

-r

Recompiles dynamically loaded modules with CPAN::Shell->recompile.

-s

Drop in the CPAN.pm shell. This command does this automatically if you don't specify any arguments.

-t module [ module ... ]

Run a `make test` on the specified modules.

-T

Do not test modules. Simply install them.

-u

Upgrade all installed modules. Blindly doing this can really break things, so keep a backup.

-v

Print the script version and CPAN.pm version then exit.

-V

Print detailed information about the cpan client.

-w

UNIMPLEMENTED

Turn on cpan warnings. This checks various things, like directory permissions, and tells you about problems you might have.

-x module [ module ... ]

Find close matches to the named modules that you think you might have mistyped. This requires the optional installation of Text::Levenshtein or Text::Levenshtein::Damerau.

-X

Dump all the namespaces to standard output.

Examples

# print a help message
cpan -h

# print the version numbers
cpan -v

# create an autobundle
cpan -a

# recompile modules
cpan -r

# upgrade all installed modules
cpan -u

# install modules ( sole -i is optional )
cpan -i Netscape::Booksmarks Business::ISBN

# force install modules ( must use -i )
cpan -fi CGI::Minimal URI

# install modules but without testing them
cpan -Ti CGI::Minimal URI

Environment variables

There are several components in CPAN.pm that use environment variables. The build tools, ExtUtils::MakeMaker and Module::Build use some, while others matter to the levels above them. Some of these are specified by the Perl Toolchain Gang:

Lancaster Concensus: https://github.com/Perl-Toolchain-Gang/toolchain-site/blob/master/lancaster-consensus.md

Oslo Concensus: https://github.com/Perl-Toolchain-Gang/toolchain-site/blob/master/oslo-consensus.md

NONINTERACTIVE_TESTING

Assume no one is paying attention and skips prompts for distributions that do that correctly. cpan(1) sets this to 1 unless it already has a value (even if that value is false).

PERL_MM_USE_DEFAULT

Use the default answer for a prompted questions. cpan(1) sets this to 1 unless it already has a value (even if that value is false).

CPAN_OPTS

As with PERL5OPT, a string of additional cpan(1) options to add to those you specify on the command line.

CPANSCRIPT_LOGLEVEL

The log level to use, with either the embedded, minimal logger or Log::Log4perl if it is installed. Possible values are the same as the Log::Log4perl levels: TRACE, DEBUG, INFO, WARN, ERROR, and FATAL. The default is INFO.

GIT_COMMAND

The path to the git binary to use for the Git features. The default is /usr/local/bin/git.

EXIT VALUES

The script exits with zero if it thinks that everything worked, or a positive number if it thinks that something failed. Note, however, that in some cases it has to divine a failure by the output of things it does not control. For now, the exit codes are vague:

1	An unknown error

2	The was an external problem

4	There was an internal problem with the script

8	A module failed to install

TO DO

* one shot configuration values from the command line

BUGS

* none noted

SEE ALSO

Most behaviour, including environment variables and configuration, comes directly from CPAN.pm.

SOURCE AVAILABILITY

This code is in Github in the CPAN.pm repository:

https://github.com/andk/cpanpm

The source used to be tracked separately in another GitHub repo, but the canonical source is now in the above repo.

CREDITS

Japheth Cleaver added the bits to allow a forced install (-f).

Jim Brandt suggest and provided the initial implementation for the up-to-date and Changes features.

Adam Kennedy pointed out that exit() causes problems on Windows where this script ends up with a .bat extension

AUTHOR

brian d foy, <bdfoy@cpan.org>

COPYRIGHT

Copyright (c) 2001-2015, brian d foy, All Rights Reserved.

You may redistribute this under the same terms as Perl itself.