CVE-2026-97794: 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 10.0.28000.3231Patch KB5127646 - 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 10.0.26100.33650Patch KB5126646 - 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 10.0.22631.7652Patch KB5126653 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5761Patch KB5126655 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26100.9711Patch KB5127648
Event History
Frequently Asked Questions
Which Microsoft products are identified as affected?
The listed affected products are Microsoft Windows 11, Microsoft Windows Server 2022, and Microsoft Windows Server 2025.
Does exploitation require local access?
Yes. The attack vector is local, and the vulnerability description specifies that an authorized attacker can exploit it locally.
What level of impact could successful exploitation have?
Successful exploitation may enable privilege elevation and is rated as having high confidentiality, integrity, and availability impact.