/ 
perl-5.40.2
⭐ Starred 2013 / Compress::Raw::Bzip2
Security Advisories (5)
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-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.

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.

NAME

Compress::Raw::Bzip2 - Low-Level Interface to bzip2 compression library

SYNOPSIS

use Compress::Raw::Bzip2 ;

my ($bz, $status) = new Compress::Raw::Bzip2 [OPTS]
    or die "Cannot create bzip2 object: $bzerno\n";

$status = $bz->bzdeflate($input, $output);
$status = $bz->bzflush($output);
$status = $bz->bzclose($output);

my ($bz, $status) = new Compress::Raw::Bunzip2 [OPTS]
    or die "Cannot create bunzip2 object: $bzerno\n";

$status = $bz->bzinflate($input, $output);

my $version = Compress::Raw::Bzip2::bzlibversion();

DESCRIPTION

Compress::Raw::Bzip2 provides an interface to the in-memory compression/uncompression functions from the bzip2 compression library.

Although the primary purpose for the existence of Compress::Raw::Bzip2 is for use by the IO::Compress::Bzip2 and IO::Compress::Bunzip2 modules, it can be used on its own for simple compression/uncompression tasks.

Compression

($z, $status) = new Compress::Raw::Bzip2 $appendOutput, $blockSize100k, $workfactor;

Creates a new compression object.

If successful, it will return the initialised compression object, $z and a $status of BZ_OK in a list context. In scalar context it returns the deflation object, $z, only.

If not successful, the returned compression object, $z, will be undef and $status will hold the a bzip2 error code.

Below is a list of the valid options:

$appendOutput

Controls whether the compressed data is appended to the output buffer in the bzdeflate, bzflush and bzclose methods.

Defaults to 1.

$blockSize100k

To quote the bzip2 documentation

blockSize100k specifies the block size to be used for compression. It
should be a value between 1 and 9 inclusive, and the actual block size
used is 100000 x this figure. 9 gives the best compression but takes
most memory.

Defaults to 1.

$workfactor

To quote the bzip2 documentation

This parameter controls how the compression phase behaves when
presented with worst case, highly repetitive, input data. If
compression runs into difficulties caused by repetitive data, the
library switches from the standard sorting algorithm to a fallback
algorithm. The fallback is slower than the standard algorithm by
perhaps a factor of three, but always behaves reasonably, no matter how
bad the input.

Lower values of workFactor reduce the amount of effort the standard
algorithm will expend before resorting to the fallback. You should set
this parameter carefully; too low, and many inputs will be handled by
the fallback algorithm and so compress rather slowly, too high, and
your average-to-worst case compression times can become very large. The
default value of 30 gives reasonable behaviour over a wide range of
circumstances.

Allowable values range from 0 to 250 inclusive. 0 is a special case,
equivalent to using the default value of 30.

Defaults to 0.

$status = $bz->bzdeflate($input, $output);

Reads the contents of $input, compresses it and writes the compressed data to $output.

Returns BZ_RUN_OK on success and a bzip2 error code on failure.

If appendOutput is enabled in the constructor for the bzip2 object, the compressed data will be appended to $output. If not enabled, $output will be truncated before the compressed data is written to it.

$status = $bz->bzflush($output);

Flushes any pending compressed data to $output.

Returns BZ_RUN_OK on success and a bzip2 error code on failure.

$status = $bz->bzclose($output);

Terminates the compressed data stream and flushes any pending compressed data to $output.

Returns BZ_STREAM_END on success and a bzip2 error code on failure.

Example

Uncompression

($z, $status) = new Compress::Raw::Bunzip2 $appendOutput, $consumeInput, $small, $verbosity, $limitOutput;

If successful, it will return the initialised uncompression object, $z and a $status of BZ_OK in a list context. In scalar context it returns the deflation object, $z, only.

If not successful, the returned uncompression object, $z, will be undef and $status will hold the a bzip2 error code.

Below is a list of the valid options:

$appendOutput

Controls whether the compressed data is appended to the output buffer in the bzinflate, bzflush and bzclose methods.

Defaults to 1.

$consumeInput
$small

To quote the bzip2 documentation

If small is nonzero, the library will use an alternative decompression
algorithm which uses less memory but at the cost of decompressing more
slowly (roughly speaking, half the speed, but the maximum memory
requirement drops to around 2300k).

Defaults to 0.

$limitOutput

The LimitOutput option changes the behavior of the $i->bzinflate method so that the amount of memory used by the output buffer can be limited.

When LimitOutput is used the size of the output buffer used will either be the 16k or the amount of memory already allocated to $output, whichever is larger. Predicting the output size available is tricky, so don't rely on getting an exact output buffer size.

When LimitOutout is not specified $i->bzinflate will use as much memory as it takes to write all the uncompressed data it creates by uncompressing the input buffer.

If LimitOutput is enabled, the ConsumeInput option will also be enabled.

This option defaults to false.

$verbosity

This parameter is ignored.

Defaults to 0.

$status = $z->bzinflate($input, $output);

Uncompresses $input and writes the uncompressed data to $output.

Returns BZ_OK if the uncompression was successful, but the end of the compressed data stream has not been reached. Returns BZ_STREAM_END on successful uncompression and the end of the compression stream has been reached.

If consumeInput is enabled in the constructor for the bunzip2 object, $input will have all compressed data removed from it after uncompression. On BZ_OK return this will mean that $input will be an empty string; when BZ_STREAM_END $input will either be an empty string or will contain whatever data immediately followed the compressed data stream.

If appendOutput is enabled in the constructor for the bunzip2 object, the uncompressed data will be appended to $output. If not enabled, $output will be truncated before the uncompressed data is written to it.

Misc

my $version = Compress::Raw::Bzip2::bzlibversion();

Returns the version of the underlying bzip2 library.

Constants

The following bzip2 constants are exported by this module

BZ_RUN
BZ_FLUSH
BZ_FINISH

BZ_OK
BZ_RUN_OK
BZ_FLUSH_OK
BZ_FINISH_OK
BZ_STREAM_END
BZ_SEQUENCE_ERROR
BZ_PARAM_ERROR
BZ_MEM_ERROR
BZ_DATA_ERROR
BZ_DATA_ERROR_MAGIC
BZ_IO_ERROR
BZ_UNEXPECTED_EOF
BZ_OUTBUFF_FULL
BZ_CONFIG_ERROR

SUPPORT

General feedback/questions/bug reports should be sent to https://github.com/pmqs/Compress-Raw-Bzip2/issues (preferred) or https://rt.cpan.org/Public/Dist/Display.html?Name=Compress-Raw-Bzip2.

SEE ALSO

Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Compress::Deflate, IO::Uncompress::Inflate, IO::Compress::RawDeflate, IO::Uncompress::RawInflate, IO::Compress::Bzip2, IO::Uncompress::Bunzip2, IO::Compress::Lzma, IO::Uncompress::UnLzma, IO::Compress::Xz, IO::Uncompress::UnXz, IO::Compress::Lzip, IO::Uncompress::UnLzip, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf, IO::Uncompress::UnLzf, IO::Compress::Zstd, IO::Uncompress::UnZstd, IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress

IO::Compress::FAQ

File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib

The primary site for the bzip2 program is https://sourceware.org/bzip2/.

See the module Compress::Bzip2

AUTHOR

This module was written by Paul Marquess, pmqs@cpan.org.

MODIFICATION HISTORY

See the Changes file.

COPYRIGHT AND LICENSE

Copyright (c) 2005-2024 Paul Marquess. All rights reserved.

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