CVE-2026-40404: Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerability

highCVSS 7.8CVE-2026-40404

CSIRTS triage

vendor: Microsoft product: Windows Universal Disk Format File System Driver (UDFS)Privilege escalation

What: This vulnerability allows elevation of privilege.
Who is affected: Deployments using the UDFS driver.
Urgency: Remediation is high urgency due to the high severity rating.
Action: Patch the UDFS driver for CVE-2026-40404.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.8
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40404

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-404040.34% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-40404	coverage & exploitation status	NVD · CVE.org

Recent advisories for Windows Universal Disk

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-40409: Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerabilitymsrc · 2026-06-09