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CVE-2025-21333

Microsoft Windows Hyper-V NT Kernel Integration VSP Heap-based Buffer Overflow

7.8 HIGHActively exploited (CISA KEV)Public exploitEPSS 9.99%
  1. Published14 Jan 2025
  2. Added to CISA KEV14 Jan 2025
  3. Remediation due4 Feb 2025
Actively exploited (CISA KEV)

Microsoft Windows Hyper-V NT Kernel Integration VSP contains a heap-based buffer overflow vulnerability that allows a local attacker to gain SYSTEM privileges.

Added to KEV: 14 Jan 2025Federal remediation due: 4 Feb 2025

Description

Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

CVSS 3.1 breakdown

Attack vectorLocal
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft Windows 10 21h2< 10.0.19044.5371
Microsoft Windows 10 22h2< 10.0.19045.5371
Microsoft Windows 11 22h2< 10.0.22621.4751
Microsoft Windows 11 23h2< 10.0.22631.4751
Microsoft Windows 11 24h2< 10.0.26100.2894
Microsoft Windows Server 2022 23h2< 10.0.25398.1369
Microsoft Windows Server 2025< 10.0.26100.2894

Remediation

Fixed in
Microsoft Windows 10 21h2≥ 10.0.19044.5371
Microsoft Windows 10 22h2≥ 10.0.19045.5371
Microsoft Windows 11 22h2≥ 10.0.22621.4751
Microsoft Windows 11 23h2≥ 10.0.22631.4751
Microsoft Windows 11 24h2≥ 10.0.26100.2894
Microsoft Windows Server 2022 23h2≥ 10.0.25398.1369
Microsoft Windows Server 2025≥ 10.0.26100.2894

References

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Frequently asked

Is CVE-2025-21333 being actively exploited?

Yes. CVE-2025-21333 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 14 Jan 2025.

How severe is CVE-2025-21333?

CVE-2025-21333 has a CVSS 3.1 base score of 7.8, rated high. EPSS estimates a 9.99% probability of exploitation.

Which products are affected by CVE-2025-21333?

Affected products include Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 22h2, Microsoft Windows 11 23h2, Microsoft Windows 11 24h2, and 2 more.

How do I fix CVE-2025-21333?

Upgrade affected software to a fixed version, for example Microsoft Windows 10 21h2 10.0.19044.5371, Microsoft Windows 10 22h2 10.0.19045.5371, Microsoft Windows 11 22h2 10.0.22621.4751 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-21333 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.