CVE-2021-31956: Microsoft Windows NTFS Privilege Escalation Vulnerability

CVE-2021-31956 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2021-11-03

Microsoft Windows NTFS contains an integer underflow vulnerability (CWE-191) that allows for local elevation of privilege. An attacker with low privileges can exploit this via a specially crafted application to gain high-level system access.

Technologies: Microsoft Windows. Vendors: Microsoft.

Quick answers

Is CVE-2021-31956 exploited in the wild?
Yes. CVE-2021-31956 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.
How severe is CVE-2021-31956?
Critical severity, with a CVSS score of 7.8, published 3 November 2021.
Which products and versions are affected?
Microsoft Windows 10 1507, 1607, 1809, 1909, 2004, 20H2, 21H1; Microsoft Windows Server 2008, 2012, 2016, 2019, 2004, 20H2; Microsoft Windows 7 SP1; Microsoft Windows 8.1 -; and 1 more.
Is there a fix for CVE-2021-31956?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2021-31956 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2021-31956?
Check whether you run Microsoft Windows. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Affected products

  • Microsoft Windows 10 1507, 1607, 1809, 1909, 2004, 20H2, 21H1
  • Microsoft Windows Server 2008, 2012, 2016, 2019, 2004, 20H2
  • Microsoft Windows 7 SP1
  • Microsoft Windows 8.1 -
  • Microsoft Windows RT 8.1 -

Timeline

  • 2021-11-03: kev added: Added to CISA Known Exploited Vulnerabilities Catalog
  • 2021-11-03: disclosed

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