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perl-5.42.2
⭐ Starred 2013 / DebugWrap
Security Advisories (3)
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-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-2026-57432 (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.

NAME

DebugWrap - wrapper to execute code under the debugger and examine the results.

SYNOPSIS

my $wrapper = DebugWrap->new(
    {
        cmds =>
        [
            # list of commands supplied to the debugger
        ],
        prog => 'filename_of_code_to_debug.pl',
        # and some optional arguments
    }
);

my $wrapper = DebugWrap->new(
    {
        cmds =>
        [
            # list of commands supplied to the debugger
        ],
        prog => \<<'EOS',
# perl code to debug
EOS
        # and some optional arguments
    }
);

# test the output from the program being debugged
$wrapper->output_like(qr/.../, "describe the test");
$wrapper->output_unlike(qr/.../, "describe the test");
my $output = $wrapper->get_output; # for more sophisticated checks

# test the output from the debugger
$wrapper->contents_like(qr/.../, "describe the test");
$wrapper->contents_unlike(qr/.../, "describe the test");
my $contents = $wrapper->get_contents; # for more sophisticated checks

DESCRIPTION

DebugWrap is a simple class used when testing the Perl debugger that executes a set of debugger commands against a program under the debugger and provides some simple methods to examine the results.

It is not installed to your system.

Creating a DebugWrap object

The constructor new() accepts a hash of arguments, with the following possible members:

cmds

An array of commands to execute, one command per element. Required.

prog

Either the name of a perl program to test under the debugger, or a reference to a scalar containing the text of the program to test. Required.

stderr

If this is a true value capture standard error, which is the default. Optional.

include_t

Add lib/perl5db/t to the perl search path, as with -I

switches

An arrayref of switches to supply to perl. This should include the -d switch needed to invoke the debugger. If switches is not supplied then -d only is supplied. The -I for include_t is added after these switches.

Other methods

The other methods intended for test usage are:

$wrapper->get_contents

Fetch the debugger output from the debugger run. This does not include the output from the program under test.

$wrapper->contents_like($re, $test_name)

Test that the debugger output matches the given regular expression object (as with qr//).

Equivalent to:

like($wrapper->get_contents, $re, $test_name);
$wrapper->contents_unlike($re, $test_name)

Test that the debugger output does not match the given regular expression object (as with qr//).

Equivalent to:

unlike($wrapper->get_contents, $re, $test_name);
$wrapper->get_output

Fetch the program output from the debugger run. This does not include the output from the debugger itself, it does include the output generated by valgrind or ASAN, assuming you haven't disabled capturing stderr.

$wrapper->output_like($re, $test_name);

Test that the program output matches the given regular expression object (as with qr//).

Equivalent to:

like($wrapper->get_output, $re, $test_name);
$wrapper->output_unlike($re, $test_name);

Test that the program output does not match the given regular expression object (as with qr//).

Equivalent to:

unlike($wrapper->get_output, $re, $test_name);