CVE-2026-72971

Analyzed Analyzed - Analysis Complete

Improper Link Resolution in Windows Container Isolation FS Filter Driver

Publication date: 2026-08-11

Last updated on: 2026-08-14

Assigner: Microsoft Corporation

Description

Improper link resolution before file access ('link following') in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to perform tampering locally.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-11

Last Modified

2026-08-14

Generated

2026-09-01

AI Q&A

2026-08-11

EPSS Evaluated

2026-08-30

NVD

CVE-2026-72971

EUVD

EUVD-2026-56603

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_11_26h1	to 10.0.28000.2704 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2704 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-59	The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Attack-Flow Graph

Executive Summary

This vulnerability is an improper link resolution issue in the Windows Container Isolation FS Filter Driver (unionfs.sys). It allows an authorized attacker to perform file tampering locally by exploiting how links are resolved before accessing files.

Detection Guidance

This vulnerability involves improper link resolution in the Windows Container Isolation FS Filter Driver. Detection requires checking for unauthorized file tampering in container environments. Review system logs for unusual activity in unionfs.sys and monitor for unexpected file modifications within container directories.

Impact Analysis

An attacker with local access could modify files within a container, potentially altering system behavior, stealing data, or escalating privileges. This could lead to unauthorized changes or disruptions in containerized environments.

Compliance Impact

This vulnerability could compromise data integrity and confidentiality in containerized systems, potentially violating compliance requirements like GDPR (data protection) or HIPAA (health data security) if exploited.

Mitigation Strategies

Apply the latest security updates from Microsoft to patch the Windows Container Isolation FS Filter Driver (unionfs.sys). Monitor Microsoft's update guide for patches and ensure all systems are updated promptly.

Hi! I’m here to help you understand CVE-2026-72971. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70