#VU57270 Improper Validation of Array Index in Microsoft Office - CVE-2021-40480

Vulnerability identifier: #VU57270

Vulnerability risk: High

CVSSv4.0: 5.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-40480

CWE-ID: CWE-129

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Microsoft Office
Client/Desktop applications / Office applications

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to improper validation of user-supplied data when parsing EMF files in Microsoft Office Visio. A remote attacker can trick the victim to open a specially crafted file, trigger memory corruption and execute arbitrary code on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Office: 2019, 2021

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External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40480
https://www.zerodayinitiative.com/advisories/ZDI-21-1159/

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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?

No. We are not aware of malware exploiting this vulnerability.