---
id: CVE-2026-96222
title: >-
  Improper certificate validation in Active Directory Federation Services (AD
  FS) allows an unauthorized attacker to perform spoofing over a network.
summary: >-
  Improper certificate validation in Active Directory Federation Services (AD
  FS) allows an unauthorized attacker to perform spoofing over a network.
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-295
vendor: System
product: System.Security.Cryptography.Xml
affected:
  - 'System.Security.Cryptography.Xml >= 8.0.0, <= 8.0.4'
patched:
  - System.Security.Cryptography.Xml 8.0.5
published: '2026-10-13'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T04:18:57.730'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-96222'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96222'
    label: secure@microsoft.com
  - url: 'https://github.com/dotnet/runtime/security/advisories/GHSA-vrv5-2jg9-4mmr'
  - url: 'https://github.com/dotnet/announcements/issues/474'
  - url: 'https://github.com/dotnet/runtime/issues/135705'
  - url: 'https://github.com/advisories/GHSA-vrv5-2jg9-4mmr'
tags:
  - nvd
  - ghsa
  - nuget
aliases:
  - GHSA-vrv5-2jg9-4mmr
ecosystem: nuget
ingestedAt: '2026-10-13T19:43:29.252Z'
---

## Overview

Improper certificate validation in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.

## Remediation

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

## Package advisory (CVE-2026-96222)

Affected packages:

- `System.Security.Cryptography.Xml >= 8.0.0, <= 8.0.4`

Patched in:

- `System.Security.Cryptography.Xml 8.0.5`

Source: https://github.com/advisories/GHSA-vrv5-2jg9-4mmr