Risk | Critical |
Patch available | YES |
Number of vulnerabilities | 1 |
CVE-ID | CVE-2021-42321 |
CWE-ID | CWE-20 |
Exploitation vector | Network |
Public exploit | This vulnerability is being exploited in the wild. |
Vulnerable software |
Microsoft Exchange Server Server applications / Mail servers |
Vendor | Microsoft |
Security Bulletin
This security bulletin contains one critical risk vulnerability.
EUVDB-ID: #VU58055
Risk: Critical
CVSSv4.0: [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/U:Red]
CVE-ID: CVE-2021-42321
CWE-ID:
CWE-20 - Improper input validation
Exploit availability: Yes
DescriptionThe vulnerability allows a remote user to compromise the affected system.
The vulnerability exists due to insufficient validation of cmdlet arguments. A remote user can run a specially crafted cmdlet and execute arbitrary commands on the system.
Note, the vulnerability is being actively exploited in the wild.
Install updates from vendor's website.
Vulnerable software versionsMicrosoft Exchange Server: 2016 Cumulative Update 1 15.01.0396.030 - 2019 RTM 15.02.0221.012
CPE2.3http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42321
http://techcommunity.microsoft.com/t5/exchange-team-blog/released-november-2021-exchange-server-security-updates/ba-p/2933169
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
Yes. This vulnerability is being exploited in the wild.