---
id: CVE-2026-20854
title: >-
  Use after free in Windows Local Security Authority Subsystem Service (LSASS)
  allows an authorized attacker to execute code over a network.
summary: >-
  Use after free in Windows Local Security Authority Subsystem Service (LSASS)
  allows an authorized attacker to execute code over a network.
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
vendor: microsoft
product: windows_11_24h2
affected:
  - windows_11_24h2 < 10.0.26100.7623
  - windows_11_25h2 < 10.0.26200.7623
  - windows_server_2025 < 10.0.26100.32230
patched:
  - windows_11_24h2 10.0.26100.7623
  - windows_11_25h2 10.0.26200.7623
  - 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-2026-20854'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20854'
    label: secure@microsoft.com
tags:
  - nvd
epss: 0.011
epssPercentile: 0.64244
ingestedAt: '2026-07-31T06:58:52.416Z'
---

## Overview

Use after free in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to execute code over a network.

## Affected

- `windows_11_24h2 < 10.0.26100.7623`
- `windows_11_25h2 < 10.0.26200.7623`
- `windows_server_2025 < 10.0.26100.32230`

## Remediation

Upgrade past the affected range:

- `windows_11_24h2 10.0.26100.7623`
- `windows_11_25h2 10.0.26200.7623`
- `windows_server_2025 10.0.26100.32230`