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perl-5.42.2
⭐ Starred 2013 / Config::Extensions
Security Advisories (1)
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.

NAME

Config::Extensions - hash lookup of which core extensions were built.

SYNOPSIS

use Config::Extensions '%Extensions';
if ($Extensions{PerlIO::via}) {
    # This perl has PerlIO::via built
}

DESCRIPTION

The Config::Extensions module provides a hash %Extensions containing all the core extensions that were enabled for this perl. The hash is keyed by extension name, with each entry having one of 3 possible values:

dynamic

The extension is dynamically linked

nonxs

The extension is pure perl, so doesn't need linking to the perl executable

static

The extension is statically linked to the perl binary

As all values evaluate to true, a simple if test is good enough to determine whether an extension is present.

All the data uses to generate the %Extensions hash is already present in the Config module, but not in such a convenient format to quickly reference.

AUTHOR

Nicholas Clark <nick@ccl4.org>