---
id: CVE-2026-20876
title: >-
  Heap-based buffer overflow in Windows Virtualization-Based Security (VBS)
  Enclave allows an authorized attacker to elevate privileges locally.
summary: >-
  Heap-based buffer overflow in Windows Virtualization-Based Security (VBS)
  Enclave allows an authorized attacker to elevate privileges locally.
severity: medium
cvss: 6.7
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-122
vendor: microsoft
product: windows_11_23h2
affected:
  - windows_11_23h2 < 10.0.22631.6491
  - windows_11_24h2 < 10.0.26100.7623
  - windows_11_25h2 < 10.0.26200.7623
  - windows_server_2022_23h2 < 10.0.25398.2092
  - windows_server_2025 < 10.0.26100.32230
patched:
  - windows_11_23h2 10.0.22631.6491
  - windows_11_24h2 10.0.26100.7623
  - windows_11_25h2 10.0.26200.7623
  - windows_server_2022_23h2 10.0.25398.2092
  - windows_server_2025 10.0.26100.32230
published: '2026-01-13'
updated: '2026-07-30'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-20876'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20876'
    label: secure@microsoft.com
tags:
  - nvd
epss: 0.00516
epssPercentile: 0.42928
ingestedAt: '2026-07-31T06:58:52.976Z'
---

## Overview

Heap-based buffer overflow in Windows Virtualization-Based Security (VBS) Enclave allows an authorized attacker to elevate privileges locally.

## Affected

- `windows_11_23h2 < 10.0.22631.6491`
- `windows_11_24h2 < 10.0.26100.7623`
- `windows_11_25h2 < 10.0.26200.7623`
- `windows_server_2022_23h2 < 10.0.25398.2092`
- `windows_server_2025 < 10.0.26100.32230`

## Remediation

Upgrade past the affected range:

- `windows_11_23h2 10.0.22631.6491`
- `windows_11_24h2 10.0.26100.7623`
- `windows_11_25h2 10.0.26200.7623`
- `windows_server_2022_23h2 10.0.25398.2092`
- `windows_server_2025 10.0.26100.32230`