/ 
perl-5.45.1
⭐ Starred 2013 / Config::Extensions
Security Advisories (1)
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.

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>