CVE-2026-97810: Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability
Heap-based buffer overflow in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.
Other sources
Windows Container Isolation FS Filter Driver (unionfs.sys) Elevation of Privilege Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26200.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26300.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26100.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.28000.3231Patch KB5127646 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26100.33650Patch KB5126646 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5761Patch KB5126655
Event History
Frequently Asked Questions
Which systems should be prioritized for review?
Prioritize Microsoft Windows 11, Windows Server 2025, Windows Server 2022, and systems using the Microsoft Windows Container Isolation FS Filter Driver.
What access does an attacker need to exploit this issue?
An attacker must already have local access and low privileges on the affected system. No user interaction is required.