CVE-2026-96222: Improper certificate validation in Active Directory Federation Services (AD FS) allows an unauthorized attacke

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HIGH 7.4REMOTEWATCHLISTUPGRADEUPGRADEMITIGATE

CVE-2026-96222 is a high-severity flaw (CVSS 7.4) affecting windows 10 1607, windows 10 1809, windows server 2012. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.4 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 54%)
CISA exploited list	No
Weakness	CWE-295
Published	2026-10-13
Last modified	2026-10-22

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Am I affected?

Timeline

2026-10-13Published CVE record published
2026-10-22 22:19 UTCUpdated Record last modified

microsoft windows 10 1607 UPGRADE

Affected: < 10.0.14393.9612

Fixed in: 10.0.14393.9612

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

microsoft windows 10 1809 UPGRADE

Affected: < 10.0.17763.9376

Fixed in: 10.0.17763.9376

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

microsoft windows server 2012 MITIGATE

Affected: all versions · r2

Fixed in: no fixed release known

Safe to downgrade to: a release before r2

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

microsoft windows server 2016 UPGRADE

Affected: < 10.0.14393.9612

Fixed in: 10.0.14393.9612

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

microsoft windows server 2019 UPGRADE

Affected: < 10.0.17763.9376

Fixed in: 10.0.17763.9376

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

microsoft windows server 2022 UPGRADE

Affected: < 10.0.20348.5761

Fixed in: 10.0.20348.5761

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

NuGet (.NET) · System.Security.Cryptography.Xml · FIXED · 8.0.5 · vulnerable: >= 8.0.0, <= 8.0.4 · source

dotnet add package System.Security.Cryptography.Xml --version 8.0.5

Fedora 46 · python-trimesh · FIXED · 5.2.0-1.fc46 · FEDORA-2026-429b4bad4c · source

sudo dnf upgrade --advisory=FEDORA-2026-429b4bad4c

Ubuntu 22.04 · dotnet6 · DEFERRED

Ubuntu 22.04 · dotnet8 · FIXED · 8.0.132-8.0.32-0ubuntu1~22.04.1

sudo apt update && sudo apt install --only-upgrade dotnet8 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dotnet8)" ge "8.0.132-8.0.32-0ubuntu1~22.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · dotnet8 · FIXED · 8.0.132-8.0.32-0ubuntu1~24.04.1

sudo apt update && sudo apt install --only-upgrade dotnet8 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dotnet8)" ge "8.0.132-8.0.32-0ubuntu1~24.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · dotnet10 · NOT AFFECTED

RHEL 10 · dotnet8.0 · FIXED · dotnet8.0-8.0.132-1.el10_2

sudo dnf upgrade --advisory=RHSA-2026:86168 rpm -q dotnet8.0

RHEL 10.0 Extended Update Support · dotnet8.0 · FIXED · dotnet8.0-8.0.132-1.el10_0

sudo dnf upgrade --advisory=RHSA-2026:88474 rpm -q dotnet8.0

RHEL 8 · dotnet8.0 · FIXED · dotnet8.0-8.0.132-2.el8_10

sudo dnf upgrade --advisory=RHSA-2026:86594 rpm -q dotnet8.0

RHEL 9 · dotnet8.0 · FIXED · dotnet8.0-8.0.132-1.el9_8

sudo dnf upgrade --advisory=RHSA-2026:86169 rpm -q dotnet8.0

RHEL 9.4 Update Services for SAP Solutions · dotnet8.0 · FIXED · dotnet8.0-8.0.132-1.el9_4

sudo dnf upgrade --advisory=RHSA-2026:88425 rpm -q dotnet8.0

Alpine 3.22 · dotnet8-runtime · FIXED · dotnet8-runtime-8.0.32-r0

apk add --upgrade dotnet8-runtime apk info -v dotnet8-runtime

Alpine 3.23 · dotnet8-runtime · FIXED · dotnet8-runtime-8.0.32-r0

apk add --upgrade dotnet8-runtime apk info -v dotnet8-runtime

Alpine 3.24 · dotnet8-runtime · FIXED · dotnet8-runtime-8.0.32-r0

apk add --upgrade dotnet8-runtime apk info -v dotnet8-runtime

Windows 10 Version 1809 for 32-bit Systems · KB5126651 · FIXED · 10.0.17763.9376 · KB5126651 · source

Install KB5126651 via Windows Update, then verify: Get-HotFix -Id KB5126651

Windows 10 Version 1809 for x64-based Systems · KB5126651 · FIXED · 10.0.17763.9376 · KB5126651 · source

Install KB5126651 via Windows Update, then verify: Get-HotFix -Id KB5126651

Windows Server 2019 · KB5126651 · FIXED · 10.0.17763.9376 · KB5126651 · source

Install KB5126651 via Windows Update, then verify: Get-HotFix -Id KB5126651

Windows Server 2019 (Server Core installation) · KB5126651 · FIXED · 10.0.17763.9376 · KB5126651 · source

Install KB5126651 via Windows Update, then verify: Get-HotFix -Id KB5126651

Windows Server 2022 · KB5126655 · FIXED · 10.0.20348.5761 · KB5126655 · source

Install KB5126655 via Windows Update, then verify: Get-HotFix -Id KB5126655

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

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References

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