Remote code execution in Microsoft Word

Published: 2021-10-12 | Updated: 2021-10-14
Risk High
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2021-40486
Exploitation vector Network
Public exploit N/A
Vulnerable software
Microsoft SharePoint Server
Server applications / Application servers

Microsoft Office Web Apps Server
Server applications / Application servers

Microsoft Office
Client/Desktop applications / Office applications

Microsoft Word
Client/Desktop applications / Office applications

Office Online Server
Server applications / Other server solutions

Vendor Microsoft

Security Bulletin

This security bulletin contains one high risk vulnerability.

1) Use-after-free

EUVDB-ID: #VU57261

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-40486

CWE-ID: CWE-416 - Use After Free

Exploit availability: No


The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error when processing DOC files in Microsoft Word. A remote attacker can trick the victim to open a specially crafted document, trigger a use-after-free error and execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.


Install updates from vendor's website.

Vulnerable software versions

Microsoft SharePoint Server: 2013 - 2019

Microsoft Office: 2013 - 2019

Office Online Server : 2016

Microsoft Word: 2013 RT Service Pack 1 - 2019

Microsoft Office Web Apps Server: 2013 Service Pack 1

External links

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.