What is CVE-2026-72971?

CVE-2026-72971 is a medium-severity vulnerability in Microsoft Windows 11 Version 26h1, classified under Improper Link Resolution Before File Access. CVSS score: 5.5/10. Published 2026-08-11.

How severe is CVE-2026-72971?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in Microsoft Windows 11 Version 26h1

CVE-2026-72971

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 v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.

Affected products

Microsoft Windows 11 Version 26h1 — versions 10.0.28000.0

Weakness classification (CWE)

CWE-59 — Improper Link Resolution Before File Access

References

Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-72971?: CVE-2026-72971 is a medium-severity vulnerability in Microsoft Windows 11 Version 26h1, classified under Improper Link Resolution Before File Access. CVSS score: 5.5/10. Published 2026-08-11.
How severe is CVE-2026-72971?: Medium severity. CVSS v3 base score is 5.5 out of 10.