/ 
perl-5.34.0-RC1
⭐ Starred 2013 / File::Spec::Unix
Security Advisories (10)
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-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-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-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.

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-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-2026-13221 (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-2026-8376 (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.

NAME

File::Spec::Unix - File::Spec for Unix, base for other File::Spec modules

SYNOPSIS

require File::Spec::Unix; # Done automatically by File::Spec

DESCRIPTION

Methods for manipulating file specifications. Other File::Spec modules, such as File::Spec::Mac, inherit from File::Spec::Unix and override specific methods.

METHODS

canonpath()

No physical check on the filesystem, but a logical cleanup of a path. On UNIX eliminates successive slashes and successive "/.".

$cpath = File::Spec->canonpath( $path ) ;

Note that this does *not* collapse x/../y sections into y. This is by design. If /foo on your system is a symlink to /bar/baz, then /foo/../quux is actually /bar/quux, not /quux as a naive ../-removal would give you. If you want to do this kind of processing, you probably want Cwd's realpath() function to actually traverse the filesystem cleaning up paths like this.

catdir()

Concatenate two or more directory names to form a complete path ending with a directory. But remove the trailing slash from the resulting string, because it doesn't look good, isn't necessary and confuses OS2. Of course, if this is the root directory, don't cut off the trailing slash :-)

catfile

Concatenate one or more directory names and a filename to form a complete path ending with a filename

curdir

Returns a string representation of the current directory. "." on UNIX.

devnull

Returns a string representation of the null device. "/dev/null" on UNIX.

rootdir

Returns a string representation of the root directory. "/" on UNIX.

tmpdir

Returns a string representation of the first writable directory from the following list or the current directory if none from the list are writable:

$ENV{TMPDIR}
/tmp

If running under taint mode, and if $ENV{TMPDIR} is tainted, it is not used.

updir

Returns a string representation of the parent directory. ".." on UNIX.

no_upwards

Given a list of file names, strip out those that refer to a parent directory. (Does not strip symlinks, only '.', '..', and equivalents.)

case_tolerant

Returns a true or false value indicating, respectively, that alphabetic is not or is significant when comparing file specifications.

file_name_is_absolute

Takes as argument a path and returns true if it is an absolute path.

This does not consult the local filesystem on Unix, Win32, OS/2 or Mac OS (Classic). It does consult the working environment for VMS (see "file_name_is_absolute" in File::Spec::VMS).

path

Takes no argument, returns the environment variable PATH as an array.

join

join is the same as catfile.

splitpath
($volume,$directories,$file) = File::Spec->splitpath( $path );
($volume,$directories,$file) = File::Spec->splitpath( $path,
                                                      $no_file );

Splits a path into volume, directory, and filename portions. On systems with no concept of volume, returns '' for volume.

For systems with no syntax differentiating filenames from directories, assumes that the last file is a path unless $no_file is true or a trailing separator or /. or /.. is present. On Unix this means that $no_file true makes this return ( '', $path, '' ).

The directory portion may or may not be returned with a trailing '/'.

The results can be passed to "catpath()" to get back a path equivalent to (usually identical to) the original path.

splitdir

The opposite of "catdir()".

@dirs = File::Spec->splitdir( $directories );

$directories must be only the directory portion of the path on systems that have the concept of a volume or that have path syntax that differentiates files from directories.

Unlike just splitting the directories on the separator, empty directory names ('') can be returned, because these are significant on some OSs.

On Unix,

File::Spec->splitdir( "/a/b//c/" );

Yields:

( '', 'a', 'b', '', 'c', '' )
catpath()

Takes volume, directory and file portions and returns an entire path. Under Unix, $volume is ignored, and directory and file are concatenated. A '/' is inserted if needed (though if the directory portion doesn't start with '/' it is not added). On other OSs, $volume is significant.

abs2rel

Takes a destination path and an optional base path returns a relative path from the base path to the destination path:

$rel_path = File::Spec->abs2rel( $path ) ;
$rel_path = File::Spec->abs2rel( $path, $base ) ;

If $base is not present or '', then cwd() is used. If $base is relative, then it is converted to absolute form using "rel2abs()". This means that it is taken to be relative to cwd().

On systems that have a grammar that indicates filenames, this ignores the $base filename. Otherwise all path components are assumed to be directories.

If $path is relative, it is converted to absolute form using "rel2abs()". This means that it is taken to be relative to cwd().

No checks against the filesystem are made, so the result may not be correct if $base contains symbolic links. (Apply Cwd::abs_path() beforehand if that is a concern.) On VMS, there is interaction with the working environment, as logicals and macros are expanded.

Based on code written by Shigio Yamaguchi.

rel2abs()

Converts a relative path to an absolute path.

$abs_path = File::Spec->rel2abs( $path ) ;
$abs_path = File::Spec->rel2abs( $path, $base ) ;

If $base is not present or '', then cwd() is used. If $base is relative, then it is converted to absolute form using "rel2abs()". This means that it is taken to be relative to cwd().

On systems that have a grammar that indicates filenames, this ignores the $base filename. Otherwise all path components are assumed to be directories.

If $path is absolute, it is cleaned up and returned using "canonpath()".

No checks against the filesystem are made. On VMS, there is interaction with the working environment, as logicals and macros are expanded.

Based on code written by Shigio Yamaguchi.

COPYRIGHT

Copyright (c) 2004 by the Perl 5 Porters. All rights reserved.

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

Please submit bug reports and patches to perlbug@perl.org.

SEE ALSO

File::Spec