What is CVE-2026-40404?

CVE-2026-40404 is a high-severity vulnerability in Microsoft Windows_10_1607, classified under Heap-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-06-09.

How severe is CVE-2026-40404?

High severity. CVSS v3 base score is 7.8 out of 10.

Buffer overflow in Microsoft Windows_10_1607

CVE-2026-40404

Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerability

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Microsoft Windows_10_1607
Microsoft Windows_10_1809
Microsoft Windows_10_21h2
Microsoft Windows_10_22h2
Microsoft Windows_11_23h2
Microsoft Windows_11_24h2
Microsoft Windows_11_25h2
Microsoft Windows_11_26h1
Microsoft Windows_server_2012 — versions r2
Microsoft Windows_server_2016

Weakness classification (CWE)

CWE-122 — Heap-based Buffer Overflow
CWE-197

References

secure@microsoft.com (Vendor Advisory)

Frequently asked questions

What is CVE-2026-40404?: CVE-2026-40404 is a high-severity vulnerability in Microsoft Windows_10_1607, classified under Heap-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-06-09.
How severe is CVE-2026-40404?: High severity. CVSS v3 base score is 7.8 out of 10.