CVE-2021-40476

Name: CVE-2021-40476
Creator: NVD / NIST
Published: 2021-10-13T01:15:11.413+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.27%

Last modified Jun 17, 2026

CVE-2021-40476 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Windows AppContainer Elevation Of Privilege Vulnerability. EPSS estimates a 2.27% chance of exploitation in the next 30 days.

Description

Windows AppContainer Elevation Of Privilege Vulnerability

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

2.27%

80.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-522

Affected Software

Vendor	Product	Versions
Microsoft	Windows 10	All versions
Microsoft	Windows 10	20h2
Microsoft	Windows 10	21h1
Microsoft	Windows 10	1607
Microsoft	Windows 10	1809
Microsoft	Windows 10	1909
Microsoft	Windows 10	2004
Microsoft	Windows 11	All versions
Microsoft	Windows 8.1	All versions
Microsoft	Windows Rt 8.1	All versions
Microsoft	Windows Server 2012	All versions
Microsoft	Windows Server 2012	r2
Microsoft	Windows Server 2016	All versions
Microsoft	Windows Server 2016	20h2
Microsoft	Windows Server 2016	2004
Microsoft	Windows Server 2019	All versions
Microsoft	Windows Server 2022	All versions

References

http://packetstormsecurity.com/files/164942/Microsoft-Windows-WSAQuerySocketSecurity-AppContainer-Privilege-Escalation.htmlThird Party Advisory, VDB Entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40476Patch, Vendor Advisory
http://packetstormsecurity.com/files/164942/Microsoft-Windows-WSAQuerySocketSecurity-AppContainer-Privilege-Escalation.htmlThird Party Advisory, VDB Entry
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40476Patch, Vendor Advisory

Timeline

Published: Oct 13, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-40476?

Windows AppContainer Elevation Of Privilege Vulnerability

How severe is CVE-2021-40476?

CVE-2021-40476 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.27% probability of exploitation in the next 30 days.

How do I fix CVE-2021-40476?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-40476?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST