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Known exploited vulnerability

CVE-2021-31166

criticalCVSS 3.1 9.8In CISA KEVEPSS 100%Published · Microsoft

The short answer

CVE-2021-31166 affects Microsoft Windows 10 Version 2004 and is rated critical (CVSS 9.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2022-04-06: attackers are using it, so patch it first. The vendor has linked a patch.

What it is

HTTP Protocol Stack Remote Code Execution Vulnerability

Weakness: CWE-416.

Severity

9.8 critical

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

Exploited (CISA KEV)

Yes, since Apr 6, 2022

Federal due date Apr 27, 2022

EPSS, next 30 days

100%

Higher than 100% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
None
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 2004, Windows Server version 2004, Windows 10 Version 20H2, Windows Server version 20H2. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2021-31166 being exploited?

Yes. CISA added CVE-2021-31166 to its Known Exploited Vulnerabilities catalog on 2022-04-06, with a federal remediation due date of 2022-04-27.

How do I fix CVE-2021-31166?

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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