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CVE-2021-31979 Microsoft CVE debrief

CVE-2021-31979 is a Microsoft Windows kernel privilege escalation vulnerability that CISA added to its Known Exploited Vulnerabilities catalog on 2021-11-03, with remediation due by 2021-11-17. Because CISA flagged it as known exploited, Windows systems should be prioritized for patching and validation even though the available source record provides limited technical detail.

Vendor
Microsoft
Product
Windows
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

Windows administrators, endpoint security teams, vulnerability management teams, and incident responders responsible for Microsoft Windows systems should treat this as a high-priority remediation item.

Technical summary

The available source corpus identifies CVE-2021-31979 as a Microsoft Windows Kernel Privilege Escalation Vulnerability. CISA’s Known Exploited Vulnerabilities record marks it as actively exploited and directs organizations to apply updates per vendor instructions. No CVSS score or deeper exploit mechanics are provided in the supplied sources.

Defensive priority

High. CISA KEV inclusion means this vulnerability should be treated as an urgent patching and exposure-management item, with remediation prioritized ahead of routine maintenance.

Recommended defensive actions

  • Apply Microsoft updates per vendor instructions as soon as possible.
  • Confirm all supported Windows endpoints and servers are covered by remediation.
  • Use vulnerability management or endpoint tooling to verify patch deployment and identify stragglers.
  • Review local administrator and privileged account hygiene to reduce the impact of privilege escalation issues.
  • Monitor Windows endpoints for suspicious privilege escalation activity or unexpected privilege changes.
  • Track remediation progress against the CISA KEV due date associated with this item.

Evidence notes

The debrief is based on the supplied CVE metadata and the CISA Known Exploited Vulnerabilities source item. Supported facts include the CVE title/description, Microsoft/Windows vendor-product mapping, and CISA’s KEV dates: added 2021-11-03 and due 2021-11-17. The corpus does not include a CVSS score or additional technical exploitation details.

Official resources

CVE published 2021-11-03. CISA added the item to the Known Exploited Vulnerabilities catalog on 2021-11-03 and set the remediation due date to 2021-11-17.