Raw vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:HSummary
CVE-2026-20867 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows 10 1809. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); 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 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-2026-20867 is a race condition vulnerability arising from concurrent execution using a shared resource with improper synchronization in Windows Management Services. Published on 2026-01-13, it carries a CVSS v3.1 base score of 7.8 (AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H) and is linked to CWEs 362 (race condition), 415 (double free), and 416 (use after free). The flaw affects Windows systems where the management services component fails to properly synchronize access to shared resources.
A local attacker with low privileges (PR:L) can exploit this vulnerability by racing to manipulate the shared resource during concurrent operations. The attack demands local access (AV:L) and high complexity (AC:H) but requires no user interaction (UI:N). Successful exploitation enables privilege escalation, with high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H), amplified by a scope change to other privileges (S:C).
Microsoft's advisory on the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20867 provides details on mitigation, including available patches for affected Windows versions. Security practitioners should review the guide for specific update instructions and apply them promptly to prevent local privilege escalation.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2150
Vulnerability Data
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Management Services allows an authorized attacker to elevate privileges locally.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 4 hardening rules · 3 OS baselines
V10.4.2V10.4.5V15.1.3V15.4.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation explicitly includes dynamic analysis and fuzzing that locate double-free defects before release.
Security engineering principles can require memory-safe allocation patterns or language features that structurally eliminate double-free opportunities.
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.
Memory protection controls limit exploitation impact by blocking unauthorized code execution from dangling pointers.
Flaw remediation processes require identification and correction of memory-management defects such as double free once discovered.
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.
Secure SDLC practices directly prevent double-free errors via static analysis, safe memory APIs, and testing.
Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.
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.
Security testing can detect race conditions, but does not prevent them at design or coding time.
Secure SDLC mandates concurrency controls and synchronization primitives that directly prevent race conditions.
Application security requirements can specify thread-safety and locking rules, but do not prescribe implementation details.
Secure architecture principles require proper synchronization and resource isolation, addressing the root cause of CWE-362.
Secure coding standards explicitly forbid unsafe concurrent access patterns and mandate atomic operations or locks.
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 (2 rules)
- V-248590 OL 8 must clear the page allocator to prevent use-after-free attacks. prevents CWE-415
- 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