CVE-2026-50324

Windows Active Directory Federation Services Denial of Service Vulnerability

Published Jul 14, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed

Description

Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.

Analysis

Technical impact

The vulnerability is an infinite loop in the Active Directory Federation Services component caused by an unreachable exit condition. The loop consumes CPU resources without termination, rendering the AD FS service unresponsive to legitimate requests of service. This weakness is classified as CWE‑835 and represents a failure in control flow that allows code to spin endlessly.

Affected Systems

Affected systems encompass Microsoft Windows 10 versions 1607 and 1809, as well as Windows Server releases 2012 R2, 2016, 2019, 2022, and 2025, including Server Core installations. The flaw applies to the AD FS role installed on each of these operating systems. In addition, the vulnerability also affects Microsoft .NET Framework 3.5 through 4.8 and the 4.8.1 version that is utilized by AD FS.

Risk and Exploitability

With a CVSS score of 5.9 the vulnerability has moderate impact, and an EPSS score of less than 1% indicates a low probability of exploitation. The vulnerability is not listed in CISA’s KEV catalog, suggesting no widespread exploitation yet. Nevertheless, an attacker who can reach the AD FS endpoint over the network could trigger the infinite loop and temporarily disrupt authentication services and any downstream applications that rely on AD FS.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Microsoft

Microsoft .NET Framework 3.5 AND 4.7.2

affected

Version	Status	Constraints
`4.7.0`	affected	< 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0

Microsoft

Microsoft .NET Framework 3.5 AND 4.8

affected

Version	Status	Constraints
`4.8.0`	affected	< 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0

Microsoft

Microsoft .NET Framework 3.5 AND 4.8.1

affected

Version	Status	Constraints
`4.8.1`	affected	< 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0

Microsoft

Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2

affected

Version	Status	Constraints
`4.7.0`	affected	< 4.7.4143.0

Microsoft

Microsoft .NET Framework 4.8

affected

Version	Status	Constraints
`4.8.0`	affected	< 4.8.4803.0

Microsoft

Microsoft .NET Framework 4.8.1

affected

Version	Status	Constraints
`4.8.0.0`	affected	< 4.8.9340.0

Microsoft

Windows 10 Version 1607

affected

Version	Status	Constraints
`10.0.14393.0`	affected	< 10.0.14393.9339

Microsoft

Windows 10 Version 1809

affected

Version	Status	Constraints
`10.0.17763.0`	affected	< 10.0.17763.9020

Microsoft

Windows Server 2012 R2

affected

Version	Status	Constraints
`6.3.9600.0`	affected	< 6.3.9600.23291

Microsoft

Windows Server 2012 R2 (Server Core installation)

affected

Version	Status	Constraints
`6.3.9600.0`	affected	< 6.3.9600.23291

Microsoft

Windows Server 2016

affected

Version	Status	Constraints
`10.0.14393.0`	affected	< 10.0.14393.9339

Microsoft

Windows Server 2016 (Server Core installation)

affected

Version	Status	Constraints
`10.0.14393.0`	affected	< 10.0.14393.9339

Microsoft

Windows Server 2019

affected

Version	Status	Constraints
`10.0.17763.0`	affected	< 10.0.17763.9020

Microsoft

Windows Server 2019 (Server Core installation)

affected

Version	Status	Constraints
`10.0.17763.0`	affected	< 10.0.17763.9020

Microsoft

Windows Server 2022

affected

Version	Status	Constraints
`10.0.20348.0`	affected	< 10.0.20348.5386

Microsoft

Windows Server 2025

affected

Version	Status	Constraints
`10.0.26100.0`	affected	< 10.0.26100.33158

Microsoft

Windows Server 2025 (Server Core installation)

affected

Version	Status	Constraints
`10.0.26100.0`	affected	< 10.0.26100.33158

Configuration 1 [-]

OR	cpe:2.3:o:microsoft:windows_10_1607:::::::x64:*
	cpe:2.3:o:microsoft:windows_10_1607:::::::x86:*
	cpe:2.3:o:microsoft:windows_10_1809:::::::x64:*
	cpe:2.3:o:microsoft:windows_10_1809:::::::x86:*
	cpe:2.3:o:microsoft:windows_server_2012:-:::::::*
	cpe:2.3:o:microsoft:windows_server_2012:r2:::::::*
	cpe:2.3:o:microsoft:windows_server_2016::::::::
	cpe:2.3:o:microsoft:windows_server_2019::::::::
	cpe:2.3:o:microsoft:windows_server_2022::::::::
	cpe:2.3:o:microsoft:windows_server_2025::::::::

No data.

Vendor Product Versions

Microsoft

.net

Version	Status	Scheme	Platform
`—`	affected	—	—

Microsoft

.net Framework

Version	Status	Scheme	Platform
`[4.7.0,4.7.4143.0)`	affected	generic	['windows_10_version_1607_for_32-bit_systems', 'windows_10_version_1607_for_x64-based_systems', 'windows_10_version_1607_for_32-bit_systems', 'windows_10_version_1607_for_x64-based_systems', 'windows_10_version_1809_for_32-bit_systems', 'windows_10_version_1809_for_x64-based_systems', 'windows_server_2016', 'windows_server_2016_(server_core_installation)', 'windows_server_2019', 'windows_server_2019_(server_core_installation)']

Microsoft

.net Framework

Version	Status	Scheme	Platform
`[4.8.0,4.8.4803.0)`	affected	generic	['windows_10_version_1809_for_32-bit_systems', 'windows_10_version_1809_for_x64-based_systems', 'windows_10_version_21h2_for_32-bit_systems', 'windows_10_version_21h2_for_arm64-based_systems', 'windows_10_version_21h2_for_x64-based_systems', 'windows_10_version_22h2_for_32-bit_systems', 'windows_10_version_22h2_for_arm64-based_systems', 'windows_10_version_22h2_for_x64-based_systems', 'windows_server_2019', 'windows_server_2019_(server_core_installation)', 'windows_server_2022', 'windows_server_2022_(server_core_installation)']

Microsoft

.net Framework

Version	Status	Scheme	Platform
`[4.8.1,4.8.9339.0)`	affected	generic	['windows_10_version_21h2_for_32-bit_systems', 'windows_10_version_21h2_for_arm64-based_systems', 'windows_10_version_21h2_for_x64-based_systems', 'windows_10_version_22h2_for_32-bit_systems', 'windows_10_version_22h2_for_arm64-based_systems', 'windows_10_version_22h2_for_x64-based_systems', 'windows_11_version_23h2_for_arm64-based_systems', 'windows_11_version_23h2_for_x64-based_systems', 'windows_11_version_24h2_for_arm64-based_systems', 'windows_11_version_24h2_for_x64-based_systems', 'windows_11_version_25h2_for_arm64-based_systems', 'windows_11_version_25h2_for_x64-based_systems', 'windows_server_2022', 'windows_server_2022_(server_core_installation)']

Microsoft

.net Framework

Version	Status	Scheme	Platform
`[4.7.0,4.7.4143.0)`	affected	generic	['windows_server_2012', 'windows_server_2012_(server_core_installation)', 'windows_server_2012_r2', 'windows_server_2012_r2_(server_core_installation)']

Microsoft

.net Framework

Version	Status	Scheme	Platform
`[4.8.0,4.8.4803.0)`	affected	generic	['windows_10_version_1607_for_32-bit_systems', 'windows_10_version_1607_for_x64-based_systems', 'windows_server_2012', 'windows_server_2012_(server_core_installation)', 'windows_server_2012_r2', 'windows_server_2012_r2_(server_core_installation)', 'windows_server_2016', 'windows_server_2016_(server_core_installation)']

Microsoft

.net Framework

Version	Status	Scheme	Platform
`[4.8.0.0,4.8.9340.0)`	affected	generic	['windows_11_version_26h1_for_arm64-based_systems', 'windows_11_version_26h1_for_x64-based_systems']

Microsoft

Windows 10 1607

Version	Status	Scheme	Platform
`[10.0.14393.0,10.0.14393.9339)`	affected	generic	['32-bit_systems', 'x64-based_systems']

Microsoft

Windows 10 1809

Version	Status	Scheme	Platform
`[10.0.17763.0,10.0.17763.9020)`	affected	generic	['32-bit_systems', 'x64-based_systems']

Microsoft

Windows Server 2012 R2

Version	Status	Scheme	Platform
`[6.3.9600.0,6.3.9600.23291)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2012 R2 (server Core Installation)

Version	Status	Scheme	Platform
`[6.3.9600.0,6.3.9600.23291)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2016

Version	Status	Scheme	Platform
`[10.0.14393.0,10.0.14393.9339)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2016 (server Core Installation)

Version	Status	Scheme	Platform
`[10.0.17763.0,10.0.17763.9020)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2019

Version	Status	Scheme	Platform
`[10.0.20348.0,10.0.20348.5386)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2019 (server Core Installation)

Version	Status	Scheme	Platform
`[10.0.26100.0,10.0.26100.33158)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2022

Version	Status	Scheme	Platform
`[10.0.26100.0,10.0.26100.33158)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2025

Version	Status	Scheme	Platform
`[10.0.26100.0,10.0.26100.33158)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2025 (server Core Installation)

Version	Status	Scheme	Platform
`[10.0.26100.0,10.0.26100.33158)`	affected	generic	['x64-based_systems']

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Install any Microsoft update that addresses CVE‑2026‑50324.
If an update is not yet available, restrict network access to the AD FS service to trusted hosts using firewall or IP‑whitelisting rules.
Continuously monitor AD FS logs and CPU usage for signs of the infinite loop; restart the AD FS service if it becomes unresponsive.

Generated by OpenCVE AI on July 31, 2026 at 08:25 UTC.

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.855% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50324

History

Nov 11, 2026 12:45 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Microsoft windows Server 2012 R2 Microsoft windows Server 2012 R2 (server Core Installation) Microsoft windows Server 2016 (server Core Installation) Microsoft windows Server 2019 (server Core Installation) Microsoft windows Server 2025 (server Core Installation)
Vendors & Products		Microsoft windows Server 2012 R2 Microsoft windows Server 2012 R2 (server Core Installation) Microsoft windows Server 2016 (server Core Installation) Microsoft windows Server 2019 (server Core Installation) Microsoft windows Server 2025 (server Core Installation)

Jul 22, 2026 4:00 PM First appearance in the feed. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Microsoft .net Framework
CPEs		cpe:2.3:a:microsoft:.net_framework::::::::
Vendors & Products		Microsoft .net Framework

Jul 16, 2026 10:15 PM First appearance in the feed. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Microsoft .net
CPEs		cpe:2.3:a:microsoft:.net::::::::
Vendors & Products		Microsoft .net

Jul 14, 2026 10:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Jul 14, 2026 5:45 PM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.
Title		Windows Active Directory Federation Services Denial of Service Vulnerability
First Time appeared		Microsoft Microsoft windows 10 1607 Microsoft windows 10 1809 Microsoft windows Server 2012 R2 Microsoft windows Server 2016 Microsoft windows Server 2019 Microsoft windows Server 2022 Microsoft windows Server 2025
Weaknesses		CWE-835
CPEs		cpe:2.3:o:microsoft:windows_10_1607:::::::x86:* cpe:2.3:o:microsoft:windows_10_1809:::::::x86:* cpe:2.3:o:microsoft:windows_server_2012_R2:::::::x64:* cpe:2.3:o:microsoft:windows_server_2016:::::::: cpe:2.3:o:microsoft:windows_server_2019:::::::: cpe:2.3:o:microsoft:windows_server_2022:::::::: cpe:2.3:o:microsoft:windows_server_2025::::::::
Vendors & Products		Microsoft Microsoft windows 10 1607 Microsoft windows 10 1809 Microsoft windows Server 2012 R2 Microsoft windows Server 2016 Microsoft windows Server 2019 Microsoft windows Server 2022 Microsoft windows Server 2025
References		https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50324
Metrics		cvssV3_1 `{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C'}`

Subscriptions

Microsoft .net .net Framework Windows 10 1607 Windows 10 1809 Windows Server 2012 Windows Server 2012 R2 Windows Server 2012 R2 Windows Server 2012 R2 (server Core Installation) Windows Server 2016 Windows Server 2016 (server Core Installation) Windows Server 2019 Windows Server 2019 (server Core Installation) Windows Server 2022 Windows Server 2025 Windows Server 2025 (server Core Installation)

Weaknesses