Remote code execution in Microsoft Word
| Risk | High |
| Patch available | YES |
| Number of vulnerabilities | 1 |
| CVE-ID | CVE-2021-40486 |
| CWE-ID | CWE-416 |
| 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
CVSSv4.0: [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-2021-40486
CWE-ID:
CWE-416 - Use After Free
Exploit availability: No
DescriptionThe 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.
MitigationInstall updates from vendor's website.
Vulnerable software versionsMicrosoft SharePoint Server: 2013 - 2019
Microsoft Office: 2013 RT - 2019
Office Online Server: 2016
Microsoft Word: 2013 RT Service Pack 1 - 2019
Microsoft Office Web Apps Server: 2013 Service Pack 1
CPE2.3- cpe:2.3:a:microsoft:microsoft_sharepoint_server:2013:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:microsoft_sharepoint_server:2016:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:microsoft_sharepoint_server:2019:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:microsoft_office:*:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:office_online_server:2016:*:*:*:*:*:*:*
- cpe:2.3:a:microsoft:microsoft_word:2013 RT Service Pack 1:*:*:*:*:microsoft_office:*:*
- cpe:2.3:a:microsoft:microsoft_word:2013 Service Pack 1:*:*:*:*:microsoft_office:*:*
- cpe:2.3:a:microsoft:microsoft_word:*:*:*:*:*:microsoft_office:*:*
- cpe:2.3:a:microsoft:microsoft_office_web_apps_server:2013 Service Pack 1:*:*:*:*:*:*:*
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40486
http://www.zerodayinitiative.com/advisories/ZDI-21-1158/
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.
