CVE-2026-50355

Windows Active Directory Federation Services Denial of Service Vulnerability

Published Jul 14, 2026 CVSS 3.1 · 7.5 High EPSS 1.2% KEV · Not listed

Description

Stack-based buffer overflow in Active Directory Federation Services allows an unauthorized attacker to deny service over a network.

Analysis

Technical impact

A stack-based buffer overflow exists in Active Directory Federation Services that can be triggered by an unauthorized attacker sending a crafted request over the network. The flaw leads to a denial of service, disrupting authentication and federation services. This weakness corresponds to CWE-121, which involves stack-based buffer overflows.

Affected Systems

The vulnerability affects Microsoft .NET Framework versions 3.5, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, and 4.8.1, as well as Microsoft Windows 10 versions 1607 and 1809, and Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025, with both standard and Server Core installations.

Risk and Exploitability

The CVSS score of 7.5 indicates a high severity, while the EPSS score of 1% reflects a low but non‑zero likelihood of exploitation. The vulnerability is not listed in CISA’s KEV catalog. It is inferred that an attacker can exploit the flaw remotely without authentication by targeting the AD FS endpoint over the network, potentially causing widespread service disruption if the affected systems are running unpatched copies.

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

affected

Version	Status	Constraints
`6.2.9200.0`	affected	< 6.2.9200.26226

Microsoft

Windows Server 2012 (Server Core installation)

affected

Version	Status	Constraints
`6.2.9200.0`	affected	< 6.2.9200.26226

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::::::::

Configuration 2 [-]

AND

cpe:2.3:a:microsoft:.net_framework:4.8.1:*:*:*:*:*:*:*

OR	cpe:2.3:o:microsoft:windows_11_26h1:-::::::arm64:
	cpe:2.3:o:microsoft:windows_11_26h1:-::::::x64:

Configuration 3 [-]

AND

cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:*

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_server_2012:-:::::::*
	cpe:2.3:o:microsoft:windows_server_2012:r2:::::::*
	cpe:2.3:o:microsoft:windows_server_2016:-:::::::*

Configuration 4 [-]

AND

OR	cpe:2.3:a:microsoft:.net_framework:4.6.2:::::::*
	cpe:2.3:a:microsoft:.net_framework:4.7:::::::*
	cpe:2.3:a:microsoft:.net_framework:4.7.1:::::::*
	cpe:2.3:a:microsoft:.net_framework:4.7.2:::::::*

OR	cpe:2.3:o:microsoft:windows_server_2012:-:::::::*
	cpe:2.3:o:microsoft:windows_server_2012:r2:::::::*

Configuration 5 [-]

AND

OR	cpe:2.3:a:microsoft:.net_framework:3.5:-::::::
	cpe:2.3:a:microsoft:.net_framework:4.8.1:::::::*

OR	cpe:2.3:o:microsoft:windows_10_21h2:-::::::arm64:
	cpe:2.3:o:microsoft:windows_10_21h2:-::::::x64:
	cpe:2.3:o:microsoft:windows_10_21h2:-::::::x86:
	cpe:2.3:o:microsoft:windows_10_22h2:-::::::arm64:
	cpe:2.3:o:microsoft:windows_10_22h2:-::::::x64:
	cpe:2.3:o:microsoft:windows_10_22h2:-::::::x86:
	cpe:2.3:o:microsoft:windows_11_23h2:-::::::arm64:
	cpe:2.3:o:microsoft:windows_11_23h2:-::::::x64:
	cpe:2.3:o:microsoft:windows_11_24h2:-::::::arm64:
	cpe:2.3:o:microsoft:windows_11_24h2:-::::::x64:
	cpe:2.3:o:microsoft:windows_11_25h2:-::::::arm64:
	cpe:2.3:o:microsoft:windows_11_25h2:-::::::x64:
	cpe:2.3:o:microsoft:windows_server_2022:-:::::::*

Configuration 6 [-]

AND

OR	cpe:2.3:a:microsoft:.net_framework:3.5:-::::::
	cpe:2.3:a:microsoft:.net_framework:4.8:::::::*

OR	cpe:2.3:o:microsoft:windows_10_1809:-::::::x64:
	cpe:2.3:o:microsoft:windows_10_1809:-::::::x86:
	cpe:2.3:o:microsoft:windows_10_21h2:-::::::arm64:
	cpe:2.3:o:microsoft:windows_10_21h2:-::::::x64:
	cpe:2.3:o:microsoft:windows_10_21h2:-::::::x86:
	cpe:2.3:o:microsoft:windows_10_22h2:-::::::arm64:
	cpe:2.3:o:microsoft:windows_10_22h2:-::::::x64:
	cpe:2.3:o:microsoft:windows_10_22h2:-::::::x86:
	cpe:2.3:o:microsoft:windows_server_2019:-:::::::*
	cpe:2.3:o:microsoft:windows_server_2022:-:::::::*

Configuration 7 [-]

AND

OR	cpe:2.3:a:microsoft:.net_framework:3.5:-::::::
	cpe:2.3:a:microsoft:.net_framework:4.7.2:::::::*

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_2016:-:::::::*
	cpe:2.3:o:microsoft:windows_server_2019:-:::::::*

No data.

Vendor Product Versions

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_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

Version	Status	Scheme	Platform
`[6.2.9200.0,6.2.9200.26226)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2012 (server Core Installation)

Version	Status	Scheme	Platform
`[6.2.9200.0,6.2.9200.26226)`	affected	generic	['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
`[10.0.14393.0,10.0.14393.9339)`	affected	generic	['x64-based_systems']

Microsoft

Windows Server 2019

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

Microsoft

Windows Server 2019 (server Core Installation)

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

Microsoft

Windows Server 2022

Version	Status	Scheme	Platform
`[10.0.20348.0,10.0.20348.5386)`	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

Apply all available security updates from Microsoft that address CVE-2026-50355 through Windows Update or by downloading the relevant cumulative updates.
If a patch cannot be applied immediately, temporarily disable the Active Directory Federation Services on the affected systems to prevent exploitation.
Configure firewall rules or network segmentation to restrict inbound access to AD FS endpoints to trusted IP ranges only.
Monitor AD FS event logs for abnormal errors or crashes that could signal attempted exploitation.

Generated by OpenCVE AI on July 31, 2026 at 08:16 UTC.

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

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: 1.2% (1.174% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50355

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 (server Core Installation) 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 (server Core Installation) 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': 'yes', '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		Stack-based buffer overflow in Active Directory Federation Services 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 Microsoft windows Server 2012 R2 Microsoft windows Server 2016 Microsoft windows Server 2019 Microsoft windows Server 2022 Microsoft windows Server 2025
Weaknesses		CWE-121
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:::::::x64:* 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 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-2026-50355
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/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 10 21h2 Windows 10 22h2 Windows 11 23h2 Windows 11 24h2 Windows 11 25h2 Windows 11 26h1 Windows Server 2012 Windows Server 2012 (server Core Installation) 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