Vulnerability identifier: #VU55726

Vulnerability risk: Medium

CVSSv3.1: 7.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2021-34480

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Windows
Operating systems & Components / Operating system
Windows Server
Operating systems & Components / Operating system
Microsoft Internet Explorer
Client/Desktop applications / Web browsers

Vendor: Microsoft

Description

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

The vulnerability exists due to incorrect JIT optimization in jscript9.dll in the Scripting Engine. A remote attacker can trick a victim to open a specially crafted file or visit a malicious website, trigger memory corruption and execute arbitrary code on the target system.

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

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: 10 - 10 S, 7, 8.1 - 8.1 RT

Windows Server: 2008 R2 - 2019 2004

Microsoft Internet Explorer: 11

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34480

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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.