Is It On KEV?

Microsoft Windows

YES - ON THE CISA KEV LIST
CVE-2025-21335

Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability

CISA catalog due date2025-02-04
overdue since 2025-02-04
EPSS exploit probability (next 30 days)1.4% · 73percentile
From CVE publication to KEV listing0 days (2025-01-14 → 2025-01-14)
Remediation window (KEV listing to due date)21 days
Days on the KEV list666 days
Date added to KEV2025-01-14
Known ransomware campaign useUnknown
VendorMicrosoft
ProductWindows
Weaknesses (CWE)CWE-416

Microsoft: 391 entries (22.0% of all KEV entries are from this vendor); 41 added in 2026.

BOD 26-04 note: this is the date printed in the CISA catalog. A federal agency's actual deadline is set by its SSVC tier - Act (3 days), Attend (14 days), Track (60 days), or the next scheduled upgrade - counted from the KEV listing date or the date the vulnerability is identified in its environment, whichever comes first. Use the tier helper on each CVE page for your own window.

Your BOD 26-04 window (SSVC tier helper)

Your remediation window ends:

Description

Microsoft Windows Hyper-V NT Kernel Integration VSP contains a use-after-free vulnerability that allows a local attacker to gain SYSTEM privileges.

Required action (CISA)

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Notes

https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-21335 ; https://nvd.nist.gov/vuln/detail/CVE-2025-21335

References

Other KEV entries for this vendor: Microsoft

Microsoft - Vendors with KEV entries

Go deeper

KEV deadlines are a governance problem as much as a patching one. TrebSec's AI governance packs help small teams document, assign, and evidence exactly this work.

AI Governance Policy Pack - $79 AI Vendor Workbook - $49 Both packs bundled - $99

Daily threat briefs at trebsec.com

Check another CVE