Cyber Resilience

CVE-2026-42836

Memory Safety in Microsoft Windows 10 21H2 ≤ 10.0.19044.7417

Published
09 June 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 0.0020 10th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-42836 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 10th 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 AC-6 (Least Privilege) — 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 Function Discovery Service (fdwsd.dll) 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 system service directly enables local privilege escalation exploit.

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

CVEs Like This One

CVE-2026-45603Same product: Microsoft Windows 10 1607
CVE-2026-45596Same product: Microsoft Windows 10 1607
CVE-2026-45601Same product: Microsoft Windows 10 1607
CVE-2026-27921Same product: Microsoft Windows 10 1607
CVE-2026-26168Same product: Microsoft Windows 10 1607
CVE-2026-33104Same product: Microsoft Windows 10 1607
CVE-2026-34331Same product: Microsoft Windows 10 1607
CVE-2026-26174Same product: Microsoft Windows 10 1607
CVE-2026-50321Same product: Microsoft Windows 10 1607
CVE-2026-50669Same product: Microsoft Windows 10 1607

Affected Assets

microsoft
windows 10 1607
≤ 10.0.14393.9234 · ≤ 10.0.14393.9234
microsoft
windows 10 1809
≤ 10.0.17763.8880 · ≤ 10.0.17763.8880
microsoft
windows 10 21h2
≤ 10.0.19044.7417 · ≤ 10.0.19044.7417 · ≤ 10.0.19044.7417
microsoft
windows 10 22h2
≤ 10.0.19045.7417 · ≤ 10.0.19045.7417 · ≤ 10.0.19045.7417
microsoft
windows 11 23h2
≤ 10.0.22631.7219 · ≤ 10.0.22631.7219
microsoft
windows 11 24h2
≤ 10.0.26100.8655 · ≤ 10.0.26100.8655
microsoft
windows 11 25h2
≤ 10.0.26200.8655 · ≤ 10.0.26200.8655
microsoft
windows 11 26h1
≤ 10.0.28000.2269 · ≤ 10.0.28000.2269
microsoft
windows server 2012
all versions, r2
microsoft
windows server 2016
≤ 10.0.14393.9234
+3 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • AC-6 Least Privilege
  • SI-16 Memory Protection
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

Enforces access mediation on the shared resource in fdwsd.dll so that a local authorized user cannot exploit the race to obtain elevated rights.

prevent

Restricts the privileges that any local process or user can hold, directly limiting the impact of a successful race-condition escalation.

prevent

Applies memory-protection mechanisms that mitigate the use-after-free component (CWE-416) that enables the race condition.

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