CVE-2021-21985
VMware — VMware vCenter Server Improper Input Validation Vulnerability
VMware · CWE-918 — Server-side request forgery | CWE-20 — Improper input validation | CWE-470 · in CISA KEV since 2021-11-03
EVRS 94 of 100 Immediate
Out-of-Band / Urgent Remediation
Rank 18 of 2,960 tracked
Why it scores 94
Evidence available: 6 of 7 signalsListed in the CISA KEV catalog, and associated with known ransomware campaigns.
- CISA KEVApplied
- RansomwareApplied
- Vendor exploitationDid not apply
- EPSSApplied
- Microsoft Exploitability IndexNot applicable
- Pre-patch disclosureNo data
- KEV recencyDid not apply
- CVSSApplied
The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data
Fix
Patch or fixed version identifiedCISA required action
Fixed in
cloud foundation: update to 3.10.2.1 or later | cloud foundation: update to 4.2.1 or later
Affected versions
- vcenter server
6.56.77.0 - cloud foundation
>= 3.0 < 3.10.2.1>= 4.0 < 4.2.1
Remediation
Apply updates per vendor instructions.
Fixed versions from NVD.
Evidence
Each value with its source| Measure | Value | Source |
|---|---|---|
| CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. | 9.8 | NVD |
| FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. | 0.999 (99.99th pctl) | FIRST EPSS |
| Actively exploitedWhether a source of record has confirmed attacks using it in the wild. | Confirmed | CISA KEV |
| Ransomware campaign useWhether CISA has seen ransomware operators use it. | Known | CISA KEV |
| CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. | 2021-11-17 · KEV since 2021 · listed over a year | CISA KEV |
| Public exploit moduleA module existing is not the same as active exploitation. | Public module exists | Metasploit |
| EUVD cross-referenceENISA's record: CVSS 9.8 (v3.1), assigned by vmware. | Listed | ENISA EUVD |
Description
NVDThe 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.
What CISA says to do
Public module
Metasploit lists a public excellent-rank module for this CVE: VMware vCenter Server Virtual SAN Health Check Plugin RCE (linux/http/vmware_vcenter_vsan_health_rce). A module existing is not the same as active exploitation; see metasploit.com.