CVE-2021-26435: Windows Scripting Engine Memory Corruption Vulnerability

Overview

Severity: High (CVSS 8.1)
CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
Category: Remote Code Execution
Exploit Status: Not Exploited
Exploitation Likelihood: Less Likely
Patch Tuesday: 2021-Sep
Released: 2021-09-14
Last Updated: 2021-09-23
EPSS Score: 7.76% (percentile: 92.0%)

FAQ

According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do? Exploitation of the vulnerability requires that a user open a specially crafted file. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) containing a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.

Affected Products (42)

Windows

Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for x64-based Systems
Windows 10 Version 1809 for ARM64-based Systems
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows 10 Version 1909 for 32-bit Systems
Windows 10 Version 1909 for x64-based Systems
Windows 10 Version 1909 for ARM64-based Systems
Windows 10 Version 21H1 for x64-based Systems
Windows 10 Version 21H1 for ARM64-based Systems
Windows 10 Version 21H1 for 32-bit Systems
Windows Server 2022
Windows Server 2022 (Server Core installation)
Windows 10 Version 2004 for 32-bit Systems
Windows 10 Version 2004 for ARM64-based Systems
Windows 10 Version 2004 for x64-based Systems
Windows Server, version 2004 (Server Core installation)
Windows 10 Version 20H2 for x64-based Systems
Windows 10 Version 20H2 for 32-bit Systems
Windows 10 Version 20H2 for ARM64-based Systems
Windows Server, version 20H2 (Server Core Installation)
Windows 10 for 32-bit Systems
Windows 10 for x64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows Server 2016
Windows Server 2016 (Server Core installation)
Windows 8.1 for 32-bit systems
Windows 8.1 for x64-based systems
Windows RT 8.1
Windows Server 2012
Windows Server 2012 (Server Core installation)
Windows Server 2012 R2
Windows Server 2012 R2 (Server Core installation)

ESU

Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems Service Pack 1
Windows Server 2008 for 32-bit Systems Service Pack 2
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
Windows Server 2008 for x64-based Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)

Security Updates (13)

Acknowledgments

Revision History

2021-09-14: Information published.
2021-09-23: For all CVEs affecting Windows that were released on September 14, 2021: 1) In the Security Updates table, the Build Numbers for KB KB5005565 have been corrected for all affected editions of the following versions of Windows 10: Windows 10, version 2004, all editions; Windows Server, version 2004 (Server Core installation); Windows 10, version 20H2; Windows Server, version 20H2 (Server Core Installation); Windows 10, version 21H1. 2) For CVEs where Windows Server 2022 is affected the links have been updated to point to information related to 5005575. Customers whose Windows devices are configured to receive automatic updates do not need to take any further action.