/ 
perl-5.40.2
⭐ Starred 2013 / Test2::Compare::Delta
Security Advisories (7)
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.

CVE-2026-15534 (2026-08-09)

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

CVE-2026-19487 (2026-08-13)

Perl versions from 5.9.4 before 5.41.9 produce incorrect regular expression match results when a stale failure flag ends the Aho-Corasick prescan early in S_find_byclass. The prescan walks the subject for positions where the full pattern could match, and the engine tries it from the leftmost one recorded. A failing transition sets the failed flag, and a later successful transition does not clear it, so the prescan reads the stale flag as a failure and stops before it can record a candidate that starts earlier. It takes a subject where one candidate is recorded and a later character then forces a fallback through a fail link that succeeds. Example: "ABCDE" =~ m/ABCF|BCDE|C/; # matches C at offset 2, not BCDE "ABCDE" =~ m/ABCF|BCDE|C(G)/; # no match, BCDE missed An alternation like this can miss input it should match, or match it on the wrong branch, so an access or filtering decision made from the result can be 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.

NAME

Test2::Compare::Delta - Representation of differences between nested data structures.

DESCRIPTION

This is used by Test2::Compare. When data structures are compared a delta will be returned. Deltas are a tree data structure that represent all the differences between two other data structures.

METHODS

CLASS METHODS

$class->add_column($NAME => sub { ... })
$class->add_column($NAME, %PARAMS)

This can be used to add columns to the table that it produced when a comparison fails. The first argument should always be the column name, which must be unique.

The first form simply takes a coderef that produces the value that should be displayed in the column for any given delta. The arguments passed into the sub are the delta, and the row ID.

Test2::Compare::Delta->add_column(
    Foo => sub {
        my ($delta, $id) = @_;
        return $delta->... ? 'foo' : 'bar'
    },
);

The second form allows you some extra options. The 'value' key is required, and must be a coderef. All other keys are optional.

Test2::Compare::Delta->add_column(
    'Foo',    # column name
    value => sub { ... },    # how to get the cell value
    alias       => 'FOO',    # Display name (used in table header)
    no_collapse => $bool,    # Show column even if it has no values?
);
$bool = $class->remove_column($NAME)

This will remove the specified column. This will return true if the column existed and was removed. This will return false if the column did not exist. No exceptions are thrown. If a missing column is a problem then you need to check the return yourself.

$class->set_column_alias($NAME, $ALIAS)

This can be used to change the table header, overriding the default column names with new ones.

ATTRIBUTES

$bool = $delta->verified
$delta->set_verified($bool)

This will be true if the delta itself matched, if the delta matched then the problem is in the delta's children, not the delta itself.

$aref = $delta->id
$delta->set_id([$type, $name])

ID for the delta, used to produce the path into the data structure. An example is ['HASH' => 'foo'] which means the delta is in the path ...->{'foo'}. Valid types are HASH, ARRAY, SCALAR, META, and METHOD.

$val = $delta->got
$delta->set_got($val)

Deltas are produced by comparing a received data structure 'got' against a check data structure 'check'. The 'got' attribute contains the value that was received for comparison.

$check = $delta->chk
$check = $delta->check
$delta->set_chk($check)
$delta->set_check($check)

Deltas are produced by comparing a received data structure 'got' against a check data structure 'check'. The 'check' attribute contains the value that was expected in the comparison.

check and chk are aliases for the same attribute.

$aref = $delta->children
$delta->set_children([$delta1, $delta2, ...])

A Delta may have child deltas. If it does then this is an arrayref with those children.

$dne = $delta->dne
$delta->set_dne($dne)

Sometimes a comparison results in one side or the other not existing at all, in which case this is set to the name of the attribute that does not exist. This can be set to 'got' or 'check'.

$e = $delta->exception
$delta->set_exception($e)

This will be set to the exception in cases where the comparison failed due to an exception being thrown.

OTHER

$string = $delta->render_got

Renders the string that should be used in a table to represent the received value in a comparison.

$string = $delta->render_check

Renders the string that should be used in a table to represent the expected value in a comparison.

$bool = $delta->should_show

This will return true if the delta should be shown in the table. This is normally true for any unverified delta. This will also be true for deltas that contain extra useful debug information.

$aref = $delta->filter_visible

This will produce an arrayref of [ $path => $delta ] for all deltas that should be displayed in the table.

$aref = $delta->table_header

This returns an array ref of the headers for the table.

$string = $delta->table_op

This returns the operator that should be shown in the table.

$string = $delta->table_check_lines

This returns the defined lines (extra debug info) that should be displayed.

$string = $delta->table_got_lines

This returns the generated lines (extra debug info) that should be displayed.

$aref = $delta->table_rows

This returns an arrayref of table rows, each row is itself an arrayref.

@table_lines = $delta->table

Returns all the lines of the table that should be displayed.

SOURCE

The source code repository for Test2-Suite can be found at https://github.com/Test-More/Test2-Suite/.

MAINTAINERS

Chad Granum <exodist@cpan.org>

AUTHORS

Chad Granum <exodist@cpan.org>

COPYRIGHT

Copyright 2018 Chad Granum <exodist@cpan.org>.

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

See http://dev.perl.org/licenses/