CVE-2026-83646: Active Directory Federation Services (AD FS) Spoofing Vulnerability

Medium severity · published Oct 13, 2026

CVE-2026-83646

Active Directory Federation Services (AD FS) Spoofing Vulnerability

4.8

CVSS

0.4%

EPSS

On KEV

Description

Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD FS) allows an authorized attacker to perform spoofing over a network.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Attack vector

Network

Complexity

Low

Privileges

High

User interaction

Required

Confidentiality

Low

Integrity

Low

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)0.4% · higher than 36% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

Windows 10 Version 1607 · Microsoft

10.0.14393.0 before 10.0.14393.9612 · source: vendor

Windows 10 Version 1809 · Microsoft

10.0.17763.0 before 10.0.17763.9376 · source: vendor

Windows Server 2016 · Microsoft

10.0.14393.0 before 10.0.14393.9612 · source: vendor

Windows Server 2016 (Server Core installation) · Microsoft

10.0.14393.0 before 10.0.14393.9612 · source: vendor

Windows Server 2019 · Microsoft

10.0.17763.0 before 10.0.17763.9376 · source: vendor

Windows Server 2019 (Server Core installation) · Microsoft

10.0.17763.0 before 10.0.17763.9376 · source: vendor

Windows Server 2022 · Microsoft

10.0.20348.0 before 10.0.20348.5761 · source: vendor

Windows Server 2025 · Microsoft

10.0.26100.0 before 10.0.26100.33650 · source: vendor

Windows Server 2025 (Server Core installation) · Microsoft

10.0.26100.0 before 10.0.26100.33650 · source: vendor

Affected product

Windows 10 Version 1607

Microsoft

All Windows 10 Version 1607 CVEs

References

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-83646

CVE.org

https://www.cve.org/CVERecord?id=CVE-2026-83646

vendor-advisory

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83646