---
id: CVE-2026-8376
title: >-
  Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0
  before 5.43.11 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…
summary: >-
  Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0
  before 5.43.11 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…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-680
vendor: perl
product: perl
affected:
  - perl <= 5.43.10
published: '2026-05-26'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T22:19:18.373'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-8376'
references:
  - url: >-
      https://github.com/Perl/perl5/commit/5e7f119eb2bb1181be908701f22bf7068e722f1c.patch
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'http://www.openwall.com/lists/oss-security/2026/05/26/1'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
  - score-dispute
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-05-27T18:03:45.554441Z'
scores:
  nvd: 9.8
  adp: 7.3
epss: 0.00443
epssPercentile: 0.3794
ingestedAt: '2026-09-08T22:12:31.038Z'
---

## Overview

Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.11 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.

## Affected

- `perl <= 5.43.10`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.