---
id: CVE-2026-85818
title: >-
  Improper verification of cryptographic signature in Windows Schannel allows an
  unauthorized attacker to perform spoofing over a network.
summary: >-
  Improper verification of cryptographic signature in Windows Schannel allows an
  unauthorized attacker to perform spoofing over a network.
severity: critical
cvss: 9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-347
published: '2026-10-13'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T23:18:50.217'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85818'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85818'
    label: secure@microsoft.com
tags:
  - nvd
ingestedAt: '2026-10-13T19:43:29.173Z'
---

## Overview

Improper verification of cryptographic signature in Windows Schannel allows an unauthorized attacker to perform spoofing over a network.

## Remediation

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