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perl-5.45.1
⭐ Starred 2013 / Win32CORE
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

Win32CORE - Win32 CORE function stubs

DESCRIPTION

This library provides stubs for the functions marked as [CORE] in Win32. See that document for usage information. When any of these functions are called, the full Win32 module is loaded automatically. It is preferred that callers of these functions explicitly use Win32;.

HISTORY

Win32CORE was created to provide on cygwin those Win32:: functions that for regular win32 builds were provided by default in perl. In cygwin perl releases prior to 5.8.6, this module was standalone and had to be explicitly used. In 5.8.6 and later, it was statically linked into cygwin perl so this would no longer be necessary.

As of perl 5.9.5/Win32 0.27, these functions have been moved into the Win32 module. Win32CORE provides stubs for each of the former CORE Win32:: functions that internally just load the Win32 module and call it's version, and Win32CORE is statically linked to perl for both cygwin and regular win32 builds. This will permit these functions to be updated in the CPAN Win32 module independently of updating perl.