CVE-2026-40409

HIGH

Published Jun 9, 2026 Modified Jun 11, 2026 CWE-197

Description

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

CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0030

Probability of exploitation

0.22%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-197 CWE-197

Affected Products

Vendor	Product	Versions
microsoft	windows_10_1607	< 10.0.14393.9234
microsoft	windows_10_1607	< 10.0.14393.9234
microsoft	windows_10_1809	< 10.0.17763.8880
microsoft	windows_10_1809	< 10.0.17763.8880
microsoft	windows_10_21h2	< 10.0.19044.7417
microsoft	windows_10_21h2	< 10.0.19044.7417
microsoft	windows_10_21h2	< 10.0.19044.7417
microsoft	windows_10_22h2	< 10.0.19045.7417
microsoft	windows_10_22h2	< 10.0.19045.7417
microsoft	windows_10_22h2	< 10.0.19045.7417
microsoft	windows_11_23h2	< 10.0.22631.7219
microsoft	windows_11_23h2	< 10.0.22631.7219
microsoft	windows_11_24h2	< 10.0.26100.8655
microsoft	windows_11_24h2	< 10.0.26100.8655
microsoft	windows_11_25h2	< 10.0.26200.8655
microsoft	windows_11_25h2	< 10.0.26200.8655
microsoft	windows_11_26h1	< 10.0.28000.2269
microsoft	windows_11_26h1	< 10.0.28000.2269
microsoft	windows_server_2012	All
microsoft	windows_server_2012	All
microsoft	windows_server_2016	< 10.0.14393.9234
microsoft	windows_server_2019	< 10.0.17763.8880
microsoft	windows_server_2022	< 10.0.20348.5256
microsoft	windows_server_2025	< 10.0.26100.32995

References

Advisories & Patches

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40409

Frequently Asked Questions

What is CVE-2026-40409? +

Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerability It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-40409? +

CVE-2026-40409 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-40409? +

CVE-2026-40409 affects products from microsoft, specifically: windows_10_1607, windows_10_1809, windows_10_21h2, windows_10_22h2, windows_11_23h2, windows_11_24h2, windows_11_25h2, windows_11_26h1, windows_server_2012, windows_server_2016, windows_server_2019, windows_server_2022, windows_server_2025. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-40409? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.