Cyber Resilience

CVE-2026-21221

Memory Safety in Microsoft Windows 11 24H2 ≤ 10.0.26100.7623

Published
13 January 2026
Modified
16 January 2026
Patch / advisory
CVSS Score v3.1 7.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0022 13th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-21221 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows 11 24H2. Its CVSS base score is 7.0 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 13th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SC-39 (Process Isolation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Concurrent execution using shared resource with improper synchronization ('race condition') in Capability Access Management Service (camsvc) allows an authorized attacker to elevate privileges locally.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Race condition (CWE-362) in local service directly enables local privilege escalation exploit (T1068).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-50458Same product: Microsoft Windows 11 24H2
CVE-2026-49806Same product: Microsoft Windows 11 24H2
CVE-2026-50385Same product: Microsoft Windows 11 24H2
CVE-2026-50414Same product: Microsoft Windows 11 24H2
CVE-2026-50345Same product: Microsoft Windows 11 24H2
CVE-2026-50322Same product: Microsoft Windows 11 24H2
CVE-2026-49802Same product: Microsoft Windows 11 24H2
CVE-2026-50398Same product: Microsoft Windows 11 24H2
CVE-2026-50305Same product: Microsoft Windows 11 24H2
CVE-2026-50317Same product: Microsoft Windows 11 24H2

Affected Assets

microsoft
windows 11 24h2
≤ 10.0.26100.7623 · ≤ 10.0.26100.7623
microsoft
windows 11 25h2
≤ 10.0.26200.7623 · ≤ 10.0.26200.7623
microsoft
windows server 2025
≤ 10.0.26100.32230

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)
  • V10.4.2
  • V10.4.5
  • V15.1.3
  • V15.4.1

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces access decisions in the Capability Access Management Service so that a race condition cannot be exploited to obtain unauthorized privileges.

prevent

Provides process isolation that reduces the ability of concurrent threads to interfere via shared resources in camsvc.

prevent

Memory protection mechanisms limit exploitation of the accompanying use-after-free weakness that enables the privilege escalation.

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 require proper synchronization primitives and concurrency testing that prevent race conditions.

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.

detects

Security testing can detect race conditions, but does not prevent them at design or coding time.

prevents

Secure SDLC mandates concurrency controls and synchronization primitives that directly prevent race conditions.

prevents

Application security requirements can specify thread-safety and locking rules, but do not prescribe implementation details.

prevents

Secure architecture principles require proper synchronization and resource isolation, addressing the root cause of CWE-362.

prevents

Secure coding standards explicitly forbid unsafe concurrent access patterns and mandate atomic operations or locks.

prevents

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

References