Vulnerability in Microsoft Windows 11 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.
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.004 (27.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 27.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.004 · change: -0.001
Affected products
- Microsoft Windows 11 26h1
- Microsoft Windows 11 Version 26h1 — versions 10.0.28000.0
Weakness classification (CWE)
References
- Windows Container Isolation FS Filter Driver (unionfs.sys) Tampering Vulnerability (vendor-advisory, Patch, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-72971?
- CVE-2026-72971 is a medium-severity vulnerability in Microsoft Windows 11 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.