CVE-2021-21985
VMware vCenter Server: Improper Input Validation
As of , CVE-2021-21985 in VMware vCenter Server is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.
- Exploited
- Yes: CISA listed it on 3 November 2021
- US federal deadline
- 17 November 202114 days after CISA listed it. US federal civilian agencies must fix it by then.
- Used in ransomware campaigns
- Known
- EPSS score
- 0.99Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
- EPSS when listed
- Not availableCISA listed it before 4 February 2022, where the EPSS files we read begin.
- Public exploit
- 1 Metasploit module
- Fix
- No vendor link in CISA's entry
What CISA says to do
Apply updates per vendor instructions.
CISA's required action
What the flaw is
VMware vSphere Client contains an improper input validation vulnerability in the Virtual SAN Health Check plug-in, which is enabled by default in vCenter Server, which allows for remote code execution.
CISA's description
The vSphere Client (HTML5) contains a remote code execution vulnerability due to lack of input validation in the Virtual SAN Health Check plug-in which is enabled by default in vCenter Server. A malicious actor with network access to port 443 may exploit this issue to execute commands with unrestricted privileges on the underlying operating system that hosts vCenter Server.
The CVE record's description, from vmware
- CVE published
- 26 May 2021
- Assigned by
- vmware
- CVSS
- 9.8 Critical (CVSS 3.1, from CISA-ADP)
- CWE-20
- Improper Input Validation
- CWE-470
- Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')
- CWE-918
- Server-Side Request Forgery (SSRF)
- CISA SSVC, exploitation
- active
- CISA SSVC, automatable
- yes
- CISA SSVC, technical impact
- total
Timeline
- The CVE record was published.
- CISA added it to its list of exploited vulnerabilities.
- The US federal deadline to fix it.
Public exploits
Facts from Metasploit's module list and Exploit-DB's index; we never copy exploit code.
- Metasploit: VMware vCenter Server Virtual SAN Health Check Plugin RCEexploit module, rank excellent
vCenter Server: other exploited entries
| Vulnerability | Product | Our group | Listed | Deadline | EPSS |
|---|---|---|---|---|---|
| CVE-2020-3952Information Disclosure | VMware vCenter Server | Patch this weekMetasploit module; EPSS 0.90 | 0.90 | ||
| CVE-2021-21972Remote Code Execution | VMware vCenter Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2021-22005File Upload | VMware vCenter Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2022-22948Incorrect Default File Permissions | VMware vCenter Server | Patch this weekMetasploit module | 0.13 | ||
| CVE-2023-34048Out-of-Bounds Write | VMware vCenter Server | Patch this weekEPSS 0.99 | 0.99 | ||
| CVE-2024-38812Heap-Based Buffer Overflow | VMware vCenter Server | Patch this weekEPSS 0.55 | 0.55 | ||
| CVE-2021-22017Improper Access Control | VMware vCenter Server | Patch soon | 0.49 | ||
| CVE-2024-38813Privilege Escalation | VMware vCenter Server | Patch soon | 0.17 |
Read further
- CVE recordcve.org
- NVD entrynvd.nist.gov
- CISA's catalogcisa.gov
- EPSS for this CVEapi.first.org