Cyber Resilience

CVE-2025-21334

Memory Safety in Microsoft Windows 11 22H2 ≤ 10.0.22621.4751

CISA KEVActive ExploitationEUVD ExploitedMemory Safety
Published
14 January 2025
Modified
27 October 2025
KEV Added
14 January 2025
Patch / advisory
View advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.016 73th percentile
Risk Priority 83 floored blend · peak EPSS

Summary

CVE-2025-21334 is a high-severity Use After Free (CWE-416) vulnerability in Microsoft Windows 11 22H2. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked in the top 27% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-21334 is a use-after-free vulnerability (CWE-416) in the Windows Hyper-V NT Kernel Integration VSP component. It carries a CVSS 3.1 score of 7.8 and affects the Hyper-V virtualization stack on supported Windows systems, allowing an attacker who already has local access to corrupt kernel memory.

A local attacker with low privileges can exploit the flaw without user interaction to escalate to SYSTEM-level privileges, resulting in full control over confidentiality, integrity, and availability of the host. The attack vector is strictly local and targets the kernel integration path between guest and host environments.

Microsoft has published guidance at the MSRC update guide for CVE-2025-21334, and the vulnerability appears in CISA’s Known Exploited Vulnerabilities catalog, indicating that patches or configuration mitigations are tracked through standard Windows update channels.

EPSS for the CVE rose from a low baseline to a recorded peak of 0.0756, demonstrating measurable post-disclosure exploitation interest that warrants renewed monitoring by defenders.

EU & UK References

Vulnerability Data

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

CWE(s)
CWE-416
KEV Date Added
14 January 2025

Related Threats

MITRE ATT&CK Enterprise Techniques

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-21335Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-30400Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-62221Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-54103Same product: Microsoft Windows 10 21H2
CVE-2025-32701Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-29824Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-32709Same product: Microsoft Windows 10 21H2both on KEV
CVE-2024-38107Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-26681Same product: Microsoft Windows 10 21H2
CVE-2025-59290Same product: Microsoft Windows 10 21H2

Affected Assets

microsoft
windows 10 21h2
≤ 10.0.19044.5371
microsoft
windows 10 22h2
≤ 10.0.19045.5371
microsoft
windows 11 22h2
≤ 10.0.22621.4751 · ≤ 10.0.22621.4751
microsoft
windows 11 23h2
≤ 10.0.22631.4751 · ≤ 10.0.22631.4751
microsoft
windows 11 24h2
≤ 10.0.26100.2894 · ≤ 10.0.26100.2894
microsoft
windows server 2022 23h2
≤ 10.0.25398.1369
microsoft
windows server 2025
≤ 10.0.26100.2894

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.4.3

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover use-after-free bugs through dynamic analysis or fuzzing.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles can require memory-safe constructs or languages that structurally avoid introducing use-after-free.

SC-39 Process Isolation partial match

Process isolation confines the blast radius of use-after-free memory corruption to a single execution domain.

SI-16 Memory Protection partial match

Memory protection controls limit exploitation impact by blocking unauthorized code execution from dangling pointers.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly incorporate memory-safety tooling and reviews that prevent most use-after-free defects.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.

PR.PS-02 partial match
prevents

Routine patching removes known use-after-free instances after they have been introduced in released software.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect use-after-free bugs before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates memory-safety practices that reduce use-after-free defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify memory-management rules that mitigate use-after-free.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles include memory-safety design choices that limit use-after-free exposure.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prescribe avoidance of use-after-free patterns.

A.8.32 Change management partial match
prevents

Change-management processes help ensure memory-safety fixes are deployed consistently.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 8 (1 rule)
  • V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 9 (1 rule)
  • V-257794 RHEL 9 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416

References