Cyber Resilience

CVE-2020-17087

Microsoft Windows Server 2016 1903 … 20h2

CISA KEVActive ExploitationEUVD Exploited
Published
11 November 2020
Modified
29 October 2025
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.054 92th percentile
Risk Priority 78 floored blend · peak EPSS

Summary

CVE-2020-17087 is a high-severity Incorrect Calculation of Buffer Size (CWE-131) vulnerability in Microsoft Windows Server 2016. Its CVSS base score is 7.8 (High).

Operationally, ranked in the top 8% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-2 (Flaw Remediation) — 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.

The vulnerability CVE-2020-17087 is a Windows Kernel Local Elevation of Privilege Vulnerability affecting the Windows kernel. It is associated with CWE-131 and has a CVSS 3.1 score of 7.8 reflecting local attack vector, low attack complexity, and low privileges required.

An attacker with local access and low privileges can exploit the flaw without user interaction to obtain full elevation of privileges, resulting in high impact to confidentiality, integrity, and availability on the affected system.

Microsoft has published security guidance for the issue via its advisory portal, and the vulnerability appears in the CISA catalog of known exploited vulnerabilities.

EU & UK References

Vulnerability Data

Windows Kernel Local Elevation of Privilege Vulnerability

CWE(s)
KEV Date Added
03 November 2021

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1068 Exploitation for Privilege Escalation Privilege Escalationconfidence: HIGH
Local kernel flaw with low privileges directly enables exploitation for privilege escalation to SYSTEM.
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2020-1380Same product: Microsoft Windows 10 1507both on KEV
CVE-2021-26411Same product: Microsoft Windows 10 1507both on KEV
CVE-2021-33742Same product: Microsoft Windows 10 1507both on KEV
CVE-2021-34448Same product: Microsoft Windows 10 1507both on KEV
CVE-2021-1675Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-0968Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-0646Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-0674Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-1464Same product: Microsoft Windows 10 1507both on KEV
CVE-2020-0878Same product: Microsoft Windows 10 1507both on KEV

Affected Assets

microsoft
windows 10 1507
all versions
microsoft
windows 10 1607
all versions
microsoft
windows 10 1803
all versions
microsoft
windows 10 1809
all versions
microsoft
windows 10 1903
all versions
microsoft
windows 10 1909
all versions
microsoft
windows 10 2004
all versions
microsoft
windows 10 20h2
all versions
microsoft
windows 7
all versions
microsoft
windows 8.1
all versions
+5 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • SI-2 Flaw Remediation
  • AC-6 Least Privilege
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces kernel-level access decisions so a low-privileged local process cannot obtain unauthorized elevated rights.

prevent

Requires timely application of the vendor patch that eliminates the buffer-size flaw before exploitation can succeed.

prevent

Limits the set of privileges initially granted to any local account, reducing the value an attacker can obtain even if the kernel flaw is triggered.

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 prevent buffer-size miscalculations via coding standards, reviews, and testing, while fixing this single weakness only partially fulfills the broader control.

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.

degrades

Secure coding standards directly require correct buffer-size calculations.

detects

Security testing can detect buffer-size errors before release.

prevents

Secure development lifecycle mandates size-checking practices that reduce buffer-size miscalculations.

prevents

Application security requirements can specify buffer-size validation rules.

prevents

Secure architecture principles include safe memory-allocation guidelines.

References