CVE-2021-40444: Microsoft MSHTML Remote Code Execution Vulnerability
In CISA’s Known Exploited Vulnerabilities catalog: Microsoft MSHTML Remote Code Execution Vulnerability.
Added , federal remediation due . Known ransomware use: Known.
Required action: Apply updates per vendor instructions.
Description
Microsoft is investigating reports of a remote code execution vulnerability in MSHTML that affects Microsoft Windows. Microsoft is aware of targeted attacks that attempt to exploit this vulnerability by using specially-crafted Microsoft Office documents. An attacker could craft a malicious ActiveX control to be used by a Microsoft Office document that hosts the browser rendering engine. The attacker would then have to convince the user to open the malicious document. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Microsoft Defender Antivirus and Microsoft Defender for Endpoint both provide detection and protections for the known vulnerability. Customers should keep antimalware products up to date. Customers who utilize automatic updates do not need to take additional action. Enterprise customers who manage updates should select the detection build 1.349.22.0 or newer and deploy it across their environments. Microsoft Defender for Endpoint alerts will be displayed as: “Suspicious Cpl File Execution”. Upon completion of this investigation, Microsoft will take the appropriate action to help protect our customers. This may include providing a security update through our monthly release process or providing an out-of-cycle security update, depending on customer needs. Please see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability. UPDATE September 14, 2021: Microsoft has released security updates to address this vulnerability. Please see the Security Updates table for the applicable update for your system. We recommend that you install these updates immediately. Please see the FAQ for important information about which updates are applicable to your system.
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L/E:P/RL:O/RC:C
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
Microsoft: Windows 10 Version 1507Microsoft: Windows 10 Version 1607Microsoft: Windows 10 Version 1809Microsoft: Windows 10 Version 1909Microsoft: Windows 10 Version 2004Microsoft: Windows 10 Version 20H2Microsoft: Windows 10 Version 21H1Microsoft: Windows 7Microsoft: Windows 7 Service Pack 1Microsoft: Windows 8.1Microsoft: Windows Server 2008 R2 Service Pack 1Microsoft: Windows Server 2008 R2 Service Pack 1 (Server Core installation)Microsoft: Windows Server 2008 Service Pack 2Microsoft: Windows Server 2008 Service Pack 2 (Server Core installation)Microsoft: Windows Server 2012Microsoft: Windows Server 2012 R2Microsoft: Windows Server 2012 R2 (Server Core installation)Microsoft: Windows Server 2012 (Server Core installation)Microsoft: Windows Server 2016Microsoft: Windows Server 2016 (Server Core installation)Microsoft: Windows Server 2019Microsoft: Windows Server 2019 (Server Core installation)Microsoft: Windows Server 2022Microsoft: Windows Server version 2004Microsoft: Windows Server version 20H2
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40444 (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)