---
id: CVE-2026-83906
title: >-
  Incorrect implementation of authentication algorithm in Windows Shell allows
  an unauthorized attacker to perform spoofing over a network.
summary: >-
  Incorrect implementation of authentication algorithm in Windows Shell allows
  an unauthorized attacker to perform spoofing over a network.
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N'
cwe:
  - CWE-303
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T23:18:37.310'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-83906'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83906'
    label: secure@microsoft.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-13T19:43:29.137Z'
vendor: Microsoft
product: Windows 11 version 23H2
affected:
  - windows_11_version_23h2 >= 10.0.22631.0 < 10.0.22631.7652
  - windows_11_version_23h2 >= 10.0.22631.0 < 10.0.22631.7652
  - windows_11_version_24h2 >= 10.0.26100.0 < 10.0.26100.9711
  - windows_11_version_25h2 >= 10.0.26200.0 < 10.0.26200.9711
  - windows_11_version_26h1 >= 10.0.28000.0 < 10.0.28000.3231
  - windows_11_version_26h2 >= 10.0.26300.0 < 10.0.26300.9711
  - windows_server_2025 >= 10.0.26100.0 < 10.0.26100.33650
  - >-
    windows_server_2025_server_core_installation >= 10.0.26100.0 <
    10.0.26100.33650
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-13T22:17:01.546430Z'
epss: 0.01011
epssPercentile: 0.62991
---

## Overview

Incorrect implementation of authentication algorithm in Windows Shell allows an unauthorized attacker to perform spoofing over a network.

## Remediation

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