Microsoft Windows Server 2016/Server 2019/Server 2022/Server 2025 Failover Cluster use after free

Summaryinfo

A vulnerability identified as very critical has been detected in Microsoft Windows Server 2016/Server 2019/Server 2022/Server 2025. Affected is an unknown function of the component Failover Cluster. This manipulation causes use after free. This vulnerability is handled as CVE-2026-119869. It is possible to launch the attack on the local host. There is not any exploit available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability has been found in Microsoft Windows Server 2016/Server 2019/Server 2022/Server 2025 and classified as very critical. Affected by this vulnerability is some unknown functionality of the component Failover Cluster. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Use after free in Windows Failover Cluster allows an authorized attacker to elevate privileges locally.

It is possible to read the advisory at msrc.microsoft.com. This vulnerability is known as CVE-2026-119869 since 10/30/2026. The exploitation appears to be easy. Attacking locally is a requirement. The exploitation needs additional levels of successful authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 11/10/2026).

Applying a patch is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Microsoft

Name

• Windows

Version

• Server 2016
• Server 2019
• Server 2022
• Server 2025

License

• commercial

Website

• Vendor: https://www.microsoft.com/
• Product: https://www.microsoft.com/en-us/windows

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