CVE intelligence and bounded remediation

CVE-2020-16939 — <p>An elevation of privilege vulnerability exists when Group Policy improperly checks access

High CVSS 7.8

<p>An elevation of privilege vulnerability exists when Group Policy improperly checks access. An attacker who successfully exploited this vulnerability could run processes in an elevated context.</p> <p>To exploit the vulnerability, an attacker would first have to log on to the system, and then run a specially crafted application to take control over the affected system.</p> <p>The security update addresses the vulnerability by correcting how Group Policy checks access.</p>

Severity
High
CVSS
7.8 (3.1)
Published
2020-10-16
CISA KEV
Not currently listed
Ecosystem
windows/system
Weaknesses
CWE-59

Affected products

  • microsoft / windows_10
  • microsoft / windows_10 / 1607
  • microsoft / windows_10 / 1709
  • microsoft / windows_10 / 1803
  • microsoft / windows_10 / 1809
  • microsoft / windows_10 / 1903

Showing 6 representative product identities from 20 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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