CVE-2026-97787

Analyzed Analyzed - Analysis Complete

Race Condition in Windows Container Isolation FS Filter Driver

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Microsoft Corporation

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to elevate privileges locally.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-97787

EUVD

EUVD-2026-100309

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_server_2022	to 10.0.20348.5761 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7652 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7652 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9711 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9711 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9711 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9711 (exc)
microsoft	windows_11_26h1	to 10.0.28000.3231 (exc)
microsoft	windows_11_26h1	to 10.0.28000.3231 (exc)
microsoft	windows_11_26h2	to 10.0.26300.9711 (exc)
microsoft	windows_11_26h2	to 10.0.26300.9711 (exc)
microsoft	windows_server_2025	to 10.0.26100.33650 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-362	The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Attack-Flow Graph

Executive Summary

This is a race condition vulnerability in the Windows Container Isolation FS Filter Driver (unionfs.sys). It occurs when concurrent execution improperly synchronizes access to shared resources, allowing an authorized attacker to elevate their privileges locally.

Impact Analysis

An attacker with local access could exploit this to gain higher privileges on your system, potentially allowing them to take control of affected Windows systems or containers.

Compliance Impact

This vulnerability allows local privilege escalation through a race condition in Windows Container Isolation FS Filter Driver. It could potentially enable unauthorized access to sensitive data or system functions, which may violate compliance requirements for data protection standards like GDPR or HIPAA if exploited in systems handling regulated data.

Mitigation Strategies

Apply the latest security updates from Microsoft to patch the Windows Container Isolation FS Filter Driver (unionfs.sys) vulnerability.

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