What is CVE-2026-62775?

CVE-2026-62775 is a medium-severity vulnerability in Microsoft Windows 11 26h1, classified under Incorrect Authorization. CVSS score: 5.5/10. Published 2026-08-11.

How severe is CVE-2026-62775?

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

Auth bypass in Microsoft Windows 11 26h1

CVE-2026-62775

Incorrect authorization in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to disclose information locally.

Vulnerability class: Broken Access Control

Published 2026-08-11 · last modified 2026-08-13.

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:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (25.9th percentile), scored 2026-09-26.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 25.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · 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)

CWE-863 — Incorrect Authorization

References

Windows Container Isolation FS Filter Driver (unionfs.sys) Information Disclosure Vulnerability (vendor-advisory, Patch, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-62775?: CVE-2026-62775 is a medium-severity vulnerability in Microsoft Windows 11 26h1, classified under Incorrect Authorization. CVSS score: 5.5/10. Published 2026-08-11.
How severe is CVE-2026-62775?: Medium severity. CVSS v3 base score is 5.5 out of 10.