What’s Vulnerable › Vulnerabilities

CVE-2020-0837: ADFS MFA Elevation of Privilege Vulnerability

• Severity: medium (CVSS 4.0 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-09-11 · updated 2026-06-17

Description

<p>An elevation of privilege vulnerability exists when Active Directory Federation Services (ADFS) improperly handles multi-factor authentication requests. An attacker who successfully exploited this vulnerability could bypass some, but not all, of the authentication factors.</p> <p>To exploit this vulnerability, an attacker could send a specially crafted authentication request.</p> <p>This security update corrects how ADFS handles multi-factor authentication requests.</p>

Affected products

• Microsoft Windows 10 Version 1607: 1607, 1809, 1903, 1909, 2004
• Microsoft Windows Server 2016: 1903, 1909, 2004
• Microsoft Windows Server 2019: all versions
• Microsoft Windows 10 1607: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1903 for 32-bit Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1903 for ARM64-based Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 Version 1903 for x64-based Systems: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 1909: from 10.0.0 before publication — fixed in publication
• Microsoft Windows 10 2004: from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server 2016: from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server 2019: from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server, version 1903 (Server Core installation): from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server, version 1909 (Server Core installation): from 10.0.0 before publication — fixed in publication
• Microsoft Windows Server version 2004: from 10.0.0 before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft Windows 10 1607 publication; Microsoft Windows 10 publication; Microsoft Windows 10 Version 1903 for 32-bit Systems publication; Microsoft Windows 10 Version 1903 for ARM64-based Systems publication; Microsoft Windows 10 Version 1903 for x64-based Systems publication; Microsoft Windows 10 1909 publication; Microsoft Windows 10 2004 publication; Microsoft Windows Server 2016 publication; Microsoft Windows Server 2019 publication; Microsoft Windows Server, version 1903 (Server Core installation) publication; Microsoft Windows Server, version 1909 (Server Core installation) publication; Microsoft Windows Server version 2004 publication. Check the vendor advisory for mitigations.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0837
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0837

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