Multiple vulnerabilities in Microsoft Excel
| Risk | High |
| Patch available | YES |
| Number of vulnerabilities | 2 |
| CVE-ID | CVE-2021-27054 CVE-2021-27053 |
| CWE-ID | CWE-416 CWE-94 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software Subscribe |
Microsoft Office Web Apps Server Server applications / Application servers Microsoft Office Client/Desktop applications / Office applications Microsoft Excel Client/Desktop applications / Office applications Office Online Server Server applications / Other server solutions |
| Vendor | Microsoft |
Security Bulletin
This security bulletin contains information about 2 vulnerabilities.
Updated: 05.05.2021
Updated description for vulnerability #1.
1) Use-after-free
EUVDB-ID: #VU51329
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-2021-27054
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 XLS files. A remote attacker can create a specially crafted Excel file, trick the victim into opening it, 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 Office Web Apps Server: 2013 Service Pack 1
Microsoft Office: 2010 Service Pack 2 - 2019 for Mac
Office Online Server : 2016
Microsoft Excel: 2010 - 2016
External linkshttp://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27054
http://www.zerodayinitiative.com/advisories/ZDI-21-507/
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.
2) Code Injection
EUVDB-ID: #VU51330
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-2021-27053
CWE-ID:
CWE-94 - Improper Control of Generation of Code ('Code Injection')
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to improper input validation in the Microsoft Excel. A remote attacker can send a specially crafted request and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
MitigationInstall updates from vendor's website.
Vulnerable software versionsMicrosoft Office: 2019
Office Online Server : 2016
Microsoft Excel: 2010 - 2016
Microsoft Office Web Apps Server: 2013 Service Pack 1
External linkshttp://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27053
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to trick the victim to visit a specially crafted website or open a file.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
