---
id: CVE-2026-84520
title: A buffer overflow was addressed with improved size validation
summary: >-
  A buffer overflow was addressed with improved size validation. This issue is
  fixed in macOS Golden Gate 27. A local attacker may be able to cause
  unexpected system termination or corrupt kernel memory.
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-120
vendor: apple
product: macos
affected:
  - macos < 27.0
patched:
  - macos 27.0
published: '2026-09-14'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T17:14:37.690'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84520'
references:
  - url: 'https://support.apple.com/en-us/149035'
    label: product-security@apple.com
tags:
  - nvd
  - cve.org
epss: 0.00445
epssPercentile: 0.36159
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-09-16T14:35:41.940952Z'
ingestedAt: '2026-09-14T21:15:17.539Z'
---

## Overview

A buffer overflow was addressed with improved size validation. This issue is fixed in macOS Golden Gate 27. A local attacker may be able to cause unexpected system termination or corrupt kernel memory.

## Affected

- `macos < 27.0`

## Remediation

Upgrade past the affected range:

- `macos 27.0`