/ 
perl-5.10.0-RC1
/ lib/IO/Zlib.pm
Security Advisories (27)
CVE-2005-3962 (2005-12-01)

Integer overflow in the format string functionality (Perl_sv_vcatpvfn) in Perl 5.9.2 and 5.8.6 Perl allows attackers to overwrite arbitrary memory and possibly execute arbitrary code via format string specifiers with large values, which causes an integer wrap and leads to a buffer overflow, as demonstrated using format string vulnerabilities in Perl applications.

CVE-2012-5195 (2012-12-18)

Heap-based buffer overflow in the Perl_repeatcpy function in util.c in Perl 5.12.x before 5.12.5, 5.14.x before 5.14.3, and 5.15.x before 15.15.5 allows context-dependent attackers to cause a denial of service (memory consumption and crash) or possibly execute arbitrary code via the 'x' string repeat operator.

CVE-2013-7422 (2015-08-16)

Integer underflow in regcomp.c in Perl before 5.20, as used in Apple OS X before 10.10.5 and other products, allows context-dependent attackers to execute arbitrary code or cause a denial of service (application crash) via a long digit string associated with an invalid backreference within a regular expression.

CVE-2011-1487 (2011-04-11)

The (1) lc, (2) lcfirst, (3) uc, and (4) ucfirst functions in Perl 5.10.x, 5.11.x, and 5.12.x through 5.12.3, and 5.13.x through 5.13.11, do not apply the taint attribute to the return value upon processing tainted input, which might allow context-dependent attackers to bypass the taint protection mechanism via a crafted string.

CVE-2011-2728 (2012-12-21)

The bsd_glob function in the File::Glob module for Perl before 5.14.2 allows context-dependent attackers to cause a denial of service (crash) via a glob expression with the GLOB_ALTDIRFUNC flag, which triggers an uninitialized pointer dereference.

CVE-2010-1158 (2010-04-20)

Integer overflow in the regular expression engine in Perl 5.8.x allows context-dependent attackers to cause a denial of service (stack consumption and application crash) by matching a crafted regular expression against a long string.

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-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-2018-6913 (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-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-2026-4176 (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-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.

CVE-2010-4777 (2014-02-10)

The Perl_reg_numbered_buff_fetch function in Perl 5.10.0, 5.12.0, 5.14.0, and other versions, when running with debugging enabled, allows context-dependent attackers to cause a denial of service (assertion failure and application exit) via crafted input that is not properly handled when using certain regular expressions, as demonstrated by causing SpamAssassin and OCSInventory to crash.

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-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-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-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-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-2013-1667 (2013-03-14)

The rehash mechanism in Perl 5.8.2 through 5.16.x allows context-dependent attackers to cause a denial of service (memory consumption and crash) via a crafted hash key.

CVE-2009-3626 (2009-10-29)

Perl 5.10.1 allows context-dependent attackers to cause a denial of service (application crash) via a UTF-8 character with a large, invalid codepoint, which is not properly handled during a regular-expression match.

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

IO::Zlib - IO:: style interface to Compress::Zlib

SYNOPSIS

With any version of Perl 5 you can use the basic OO interface:

use IO::Zlib;

$fh = new IO::Zlib;
if ($fh->open("file.gz", "rb")) {
    print <$fh>;
    $fh->close;
}

$fh = IO::Zlib->new("file.gz", "wb9");
if (defined $fh) {
    print $fh "bar\n";
    $fh->close;
}

$fh = IO::Zlib->new("file.gz", "rb");
if (defined $fh) {
    print <$fh>;
    undef $fh;       # automatically closes the file
}

With Perl 5.004 you can also use the TIEHANDLE interface to access compressed files just like ordinary files:

use IO::Zlib;

tie *FILE, 'IO::Zlib', "file.gz", "wb";
print FILE "line 1\nline2\n";

tie *FILE, 'IO::Zlib', "file.gz", "rb";
while (<FILE>) { print "LINE: ", $_ };

DESCRIPTION

IO::Zlib provides an IO:: style interface to Compress::Zlib and hence to gzip/zlib compressed files. It provides many of the same methods as the IO::Handle interface.

Starting from IO::Zlib version 1.02, IO::Zlib can also use an external gzip command. The default behaviour is to try to use an external gzip if no Compress::Zlib can be loaded, unless explicitly disabled by

use IO::Zlib qw(:gzip_external 0);

If explicitly enabled by

use IO::Zlib qw(:gzip_external 1);

then the external gzip is used instead of Compress::Zlib.

CONSTRUCTOR

new ( [ARGS] )

Creates an IO::Zlib object. If it receives any parameters, they are passed to the method open; if the open fails, the object is destroyed. Otherwise, it is returned to the caller.

OBJECT METHODS

open ( FILENAME, MODE )

open takes two arguments. The first is the name of the file to open and the second is the open mode. The mode can be anything acceptable to Compress::Zlib and by extension anything acceptable to zlib (that basically means POSIX fopen() style mode strings plus an optional number to indicate the compression level).

opened

Returns true if the object currently refers to a opened file.

close

Close the file associated with the object and disassociate the file from the handle. Done automatically on destroy.

getc

Return the next character from the file, or undef if none remain.

getline

Return the next line from the file, or undef on end of string. Can safely be called in an array context. Currently ignores $/ ($INPUT_RECORD_SEPARATOR or $RS when English is in use) and treats lines as delimited by "\n".

getlines

Get all remaining lines from the file. It will croak() if accidentally called in a scalar context.

Print ARGS to the file.

read ( BUF, NBYTES, [OFFSET] )

Read some bytes from the file. Returns the number of bytes actually read, 0 on end-of-file, undef on error.

eof

Returns true if the handle is currently positioned at end of file?

seek ( OFFSET, WHENCE )

Seek to a given position in the stream. Not yet supported.

tell

Return the current position in the stream, as a numeric offset. Not yet supported.

setpos ( POS )

Set the current position, using the opaque value returned by getpos(). Not yet supported.

getpos ( POS )

Return the current position in the string, as an opaque object. Not yet supported.

USING THE EXTERNAL GZIP

If the external gzip is used, the following opens are used:

open(FH, "gzip -dc $filename |")  # for read opens
open(FH, " | gzip > $filename")   # for write opens

You can modify the 'commands' for example to hardwire an absolute path by e.g.

use IO::Zlib ':gzip_read_open'  => '/some/where/gunzip -c %s |';
use IO::Zlib ':gzip_write_open' => '| /some/where/gzip.exe > %s';

The %s is expanded to be the filename (sprintf is used, so be careful to escape any other % signs). The 'commands' are checked for sanity - they must contain the %s, and the read open must end with the pipe sign, and the write open must begin with the pipe sign.

CLASS METHODS

has_Compress_Zlib

Returns true if Compress::Zlib is available. Note that this does not mean that Compress::Zlib is being used: see "gzip_external" and gzip_used.

gzip_external

Undef if an external gzip can be used if Compress::Zlib is not available (see "has_Compress_Zlib"), true if an external gzip is explicitly used, false if an external gzip must not be used. See "gzip_used".

gzip_used

True if an external gzip is being used, false if not.

gzip_read_open

Return the 'command' being used for opening a file for reading using an external gzip.

gzip_write_open

Return the 'command' being used for opening a file for writing using an external gzip.

DIAGNOSTICS

IO::Zlib::getlines: must be called in list context

If you want read lines, you must read in list context.

IO::Zlib::gzopen_external: mode '...' is illegal

Use only modes 'rb' or 'wb' or /wb[1-9]/.

IO::Zlib::import: '...' is illegal

The known import symbols are the :gzip_external, :gzip_read_open, and :gzip_write_open. Anything else is not recognized.

IO::Zlib::import: ':gzip_external' requires an argument

The :gzip_external requires one boolean argument.

IO::Zlib::import: 'gzip_read_open' requires an argument

The :gzip_external requires one string argument.

IO::Zlib::import: 'gzip_read' '...' is illegal

The :gzip_read_open argument must end with the pipe sign (|) and have the %s for the filename. See "USING THE EXTERNAL GZIP".

IO::Zlib::import: 'gzip_write_open' requires an argument

The :gzip_external requires one string argument.

IO::Zlib::import: 'gzip_write_open' '...' is illegal

The :gzip_write_open argument must begin with the pipe sign (|) and have the %s for the filename. An output redirect (>) is also often a good idea, depending on your operating system shell syntax. See "USING THE EXTERNAL GZIP".

IO::Zlib::import: no Compress::Zlib and no external gzip

Given that we failed to load Compress::Zlib and that the use of an external gzip was disabled, IO::Zlib has not much chance of working.

IO::Zlib::open: needs a filename

No filename, no open.

IO::Zlib::READ: NBYTES must be specified

We must know how much to read.

IO::Zlib::WRITE: too long LENGTH

The LENGTH must be less than or equal to the buffer size.

IO::Zlib::WRITE: OFFSET is not supported

Offsets of gzipped streams are not supported.

SEE ALSO

perlfunc, "I/O Operators" in perlop, IO::Handle, Compress::Zlib

HISTORY

Created by Tom Hughes <tom@compton.nu>.

Support for external gzip added by Jarkko Hietaniemi <jhi@iki.fi>.

COPYRIGHT

Copyright (c) 1998-2004 Tom Hughes <tom@compton.nu>. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.