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perl-5.41.3
⭐ Starred 2013 / TAP::Parser::Grammar
Security Advisories (8)
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-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-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.

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-2026-19487 (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

TAP::Parser::Grammar - A grammar for the Test Anything Protocol.

VERSION

Version 3.50

SYNOPSIS

use TAP::Parser::Grammar;
my $grammar = $self->make_grammar({
  iterator => $tap_parser_iterator,
  parser   => $tap_parser,
  version  => 12,
});

my $result = $grammar->tokenize;

DESCRIPTION

TAP::Parser::Grammar tokenizes lines from a TAP::Parser::Iterator and constructs TAP::Parser::Result subclasses to represent the tokens.

Do not attempt to use this class directly. It won't make sense. It's mainly here to ensure that we will be able to have pluggable grammars when TAP is expanded at some future date (plus, this stuff was really cluttering the parser).

METHODS

Class Methods

new

my $grammar = TAP::Parser::Grammar->new({
    iterator => $iterator,
    parser   => $parser,
    version  => $version,
});

Returns TAP::Parser grammar object that will parse the TAP stream from the specified iterator. Both iterator and parser are required arguments. If version is not set it defaults to 12 (see "set_version" for more details).

Instance Methods

set_version

$grammar->set_version(13);

Tell the grammar which TAP syntax version to support. The lowest supported version is 12. Although 'TAP version' isn't valid version 12 syntax it is accepted so that higher version numbers may be parsed.

tokenize

my $token = $grammar->tokenize;

This method will return a TAP::Parser::Result object representing the current line of TAP.

token_types

my @types = $grammar->token_types;

Returns the different types of tokens which this grammar can parse.

syntax_for

my $syntax = $grammar->syntax_for($token_type);

Returns a pre-compiled regular expression which will match a chunk of TAP corresponding to the token type. For example (not that you should really pay attention to this, $grammar->syntax_for('comment') will return qr/^#(.*)/.

handler_for

my $handler = $grammar->handler_for($token_type);

Returns a code reference which, when passed an appropriate line of TAP, returns the lexed token corresponding to that line. As a result, the basic TAP parsing loop looks similar to the following:

my @tokens;
my $grammar = TAP::Grammar->new;
LINE: while ( defined( my $line = $parser->_next_chunk_of_tap ) ) {
    for my $type ( $grammar->token_types ) {
        my $syntax  = $grammar->syntax_for($type);
        if ( $line =~ $syntax ) {
            my $handler = $grammar->handler_for($type);
            push @tokens => $grammar->$handler($line);
            next LINE;
        }
    }
    push @tokens => $grammar->_make_unknown_token($line);
}

TAP GRAMMAR

NOTE: This grammar is slightly out of date. There's still some discussion about it and a new one will be provided when we have things better defined.

The TAP::Parser does not use a formal grammar because TAP is essentially a stream-based protocol. In fact, it's quite legal to have an infinite stream. For the same reason that we don't apply regexes to streams, we're not using a formal grammar here. Instead, we parse the TAP in lines.

For purposes for forward compatibility, any result which does not match the following grammar is currently referred to as TAP::Parser::Result::Unknown. It is not a parse error.

A formal grammar would look similar to the following:

(*
    For the time being, I'm cheating on the EBNF by allowing
    certain terms to be defined by POSIX character classes by
    using the following syntax:

      digit ::= [:digit:]

    As far as I am aware, that's not valid EBNF.  Sue me.  I
    didn't know how to write "char" otherwise (Unicode issues).
    Suggestions welcome.
*)

tap            ::= version? { comment | unknown } leading_plan lines
                   |
                   lines trailing_plan {comment}

version        ::= 'TAP version ' positiveInteger {positiveInteger} "\n"

leading_plan   ::= plan skip_directive? "\n"

trailing_plan  ::= plan "\n"

plan           ::= '1..' nonNegativeInteger

lines          ::= line {line}

line           ::= (comment | test | unknown | bailout ) "\n"

test           ::= status positiveInteger? description? directive?

status         ::= 'not '? 'ok '

description    ::= (character - (digit | '#')) {character - '#'}

directive      ::= todo_directive | skip_directive

todo_directive ::= hash_mark 'TODO' ' ' {character}

skip_directive ::= hash_mark 'SKIP' ' ' {character}

comment        ::= hash_mark {character}

hash_mark      ::= '#' {' '}

bailout        ::= 'Bail out!' {character}

unknown        ::= { (character - "\n") }

(* POSIX character classes and other terminals *)

digit              ::= [:digit:]
character          ::= ([:print:] - "\n")
positiveInteger    ::= ( digit - '0' ) {digit}
nonNegativeInteger ::= digit {digit}

SUBCLASSING

Please see "SUBCLASSING" in TAP::Parser for a subclassing overview.

If you really want to subclass TAP::Parser's grammar the best thing to do is read through the code. There's no easy way of summarizing it here.

SEE ALSO

TAP::Object, TAP::Parser, TAP::Parser::Iterator, TAP::Parser::Result,