Remote code execution in Microsoft MSHTML



Published: 2021-09-07 | Updated: 2021-09-14
Risk Critical
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2021-40444
CWE ID CWE-94
Exploitation vector Network
Public exploit This vulnerability is being exploited in the wild.
Vulnerable software
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Windows
Operating systems & Components / Operating system

Windows Server
Operating systems & Components / Operating system

Microsoft Internet Explorer
Client/Desktop applications / Web browsers

Vendor Microsoft

Security Advisory

Updated: 14.09.2021

Changed bulletin status to patched.

1) Code Injection

Risk: Critical

CVSSv3.1: 8.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C] [PCI]

CVE-ID: CVE-2021-40444

CWE-ID: CWE-94 - Improper Control of Generation of Code ('Code Injection')

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to improper input validation within the MSHTML component. A remote attacker can create a specially crafted Office document with a malicious ActiveX control inside, trick the victim into opening the document and execute arbitrary code on the system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Note, the vulnerability is being actively exploited in the wild.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Windows: 8.1, 10, 10 20H2, 10 21H1, 10 1507, 10 1511, 10 1607, 10 1703, 10 1709, 10 1803, 10 1809, 10 1903, 10 1909, 10 2004, 10 Gold, 10 Mobile, 10 S, RT 8.1

Windows Server: 2008, 2008 R2, 2012, 2012 R2, 2016, 2019, 2019 20H2, 2019 2004

Microsoft Internet Explorer: 11

CPE External links

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40444

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.



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