Cyber Resilience

CVE-2026-20869

Race Condition in Microsoft Windows Server 2008 r2

Published
13 January 2026
Modified
30 July 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 0.0030 22th percentile
Risk Priority 51 floored blend · peak EPSS

Summary

CVE-2026-20869 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows Server 2008. 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 22th 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 SC-39 (Process Isolation) and SC-4 (Information in Shared System Resources) — 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 Local Session Manager (LSM) allows an authorized attacker to elevate privileges locally.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-20927Same product: Microsoft Windows 10 1607
CVE-2025-62217Same product: Microsoft Windows 10 1607
CVE-2026-20921Same product: Microsoft Windows 10 1607
CVE-2026-20848Same product: Microsoft Windows 10 1607
CVE-2026-20934Same product: Microsoft Windows 10 1607
CVE-2025-59506Same product: Microsoft Windows 10 1607
CVE-2026-20919Same product: Microsoft Windows 10 1607
CVE-2026-21231Same product: Microsoft Windows 10 1607
CVE-2026-20926Same product: Microsoft Windows 10 1607
CVE-2025-59205Same product: Microsoft Windows 10 1607

Affected Assets

microsoft
windows 10 1607
≤ 10.0.14393.8783 · ≤ 10.0.14393.8783
microsoft
windows 10 1809
≤ 10.0.17763.8276 · ≤ 10.0.17763.8276
microsoft
windows 10 21h2
≤ 10.0.19044.6809
microsoft
windows 10 22h2
≤ 10.0.19045.6809
microsoft
windows 11 23h2
≤ 10.0.22631.6491
microsoft
windows 11 24h2
≤ 10.0.26100.7623
microsoft
windows 11 25h2
≤ 10.0.26200.7623
microsoft
windows server 2008
all versions, r2
microsoft
windows server 2012
all versions, r2
microsoft
windows server 2016
≤ 10.0.14393.8783
+4 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

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

Maintaining separate execution domains for each process structurally eliminates unintended concurrent access to the same shared resources.

Preventing unintended information transfer through shared system resources directly addresses the improper concurrent modification that defines a 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.

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.

finds

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