Cyber Resilience

CVE-2026-33839

Race Condition in Microsoft Windows 10 21H2 ≤ 10.0.19044.7291

Published
12 May 2026
Modified
17 June 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 0.0019 9th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-33839 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows 10 21H2. 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 9th 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-6 (Least Privilege) 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 Windows Win32K - GRFX 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 in Win32K kernel component directly enables local privilege escalation via vulnerability exploitation (T1068).

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

CVEs Like This One

CVE-2026-27918Same product: Microsoft Windows 10 1809
CVE-2026-32160Same product: Microsoft Windows 10 1809
CVE-2026-20866Same product: Microsoft Windows 10 1809
CVE-2026-20930Same product: Microsoft Windows 10 1809
CVE-2025-64658Same product: Microsoft Windows 10 1809
CVE-2026-42977Same product: Microsoft Windows 10 1809
CVE-2026-21234Same product: Microsoft Windows 10 1809
CVE-2026-32164Same product: Microsoft Windows 10 1809
CVE-2026-50378Same product: Microsoft Windows 10 1809
CVE-2026-50450Same product: Microsoft Windows 10 1809

Affected Assets

microsoft
windows 10 1809
≤ 10.0.17763.8755 · ≤ 10.0.17763.8755
microsoft
windows 10 21h2
≤ 10.0.19044.7291 · ≤ 10.0.19044.7291 · ≤ 10.0.19044.7291
microsoft
windows 10 22h2
≤ 10.0.19045.7291 · ≤ 10.0.19045.7291 · ≤ 10.0.19045.7291
microsoft
windows 11 23h2
≤ 10.0.22631.7079 · ≤ 10.0.22631.7079
microsoft
windows 11 24h2
≤ 10.0.26100.8390 · ≤ 10.0.26100.8390
microsoft
windows 11 25h2
≤ 10.0.26200.8390 · ≤ 10.0.26200.8390
microsoft
windows 11 26h1
≤ 10.0.28000.2113 · ≤ 10.0.28000.2113
microsoft
windows server 2019
≤ 10.0.17763.8755
microsoft
windows server 2022
≤ 10.0.20348.5074
microsoft
windows server 2022 23h2
≤ 10.0.25398.2330
+1 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-6 Least Privilege
  • SC-39 Process Isolation
  • AC-3 Access Enforcement
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

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 limits the initial privileges of the authorized local attacker, reducing the impact and feasibility of successful Win32K privilege escalation via the race condition.

prevent

Enforces process isolation boundaries that mitigate improper synchronization on shared kernel graphics resources exploited by CWE-362.

prevent

Enforces access decisions on kernel objects and graphics resources, blocking unauthorized elevation paths even for locally authenticated users.

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.

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.

none

Change management reduces introduction of concurrency bugs during updates, yet does not address the weakness itself.

References