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Known exploited vulnerability

CVE-2021-31956

highCVSS 3.1 7.8In CISA KEVEPSS 22%Published · Microsoft

The short answer

CVE-2021-31956 affects Microsoft Windows 10 Version 1809 and is rated high (CVSS 7.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2021-11-03: attackers are using it, so patch it first. The vendor has linked a patch.

What it is

Windows NTFS Elevation of Privilege Vulnerability

Weakness: CWE-191.

Severity

7.8 high

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploited (CISA KEV)

Yes, since Nov 3, 2021

Federal due date Nov 17, 2021

EPSS, next 30 days

22%

Higher than 98% of scored CVEs

How it can be exploited

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

Apply updates per vendor instructions.

Affected products

Windows 10 Version 1809, Windows Server 2019, Windows Server 2019 (Server Core installation), Windows 10 Version 1909, Windows 10 Version 21H1, Windows 10 Version 2004, Windows Server version 2004, Windows 10 Version 20H2, Windows Server version 20H2, Windows 10 Version 1507, Windows 10 Version 1607, Windows Server 2016. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2021-31956 being exploited?

Yes. CISA added CVE-2021-31956 to its Known Exploited Vulnerabilities catalog on 2021-11-03, with a federal remediation due date of 2021-11-17.

How do I fix CVE-2021-31956?

CISA's required action: Apply updates per vendor instructions.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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