CVE-2021-21985

CRITICAL KEV RANSOMWARE NUCLEI

VMware vCenter Server - Remote Code Execution via Virtual SAN Health Check Plugin

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2021-21985 is actively exploited and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added November 3, 2021, with confirmed use in ransomware campaigns. EIP tracks 14 public exploits from researchers including alt3kx, xnianq, testanull, including a Metasploit module exploits/linux/http/vmware_vcenter_vsan_health_rce. A Nuclei detection template is also available.

AI-analyzed exploit summary This repository provides a functional proof-of-concept exploit for CVE-2021-21985, a remote code execution vulnerability in VMware vCenter Server's Virtual SAN Health Check plug-in. The exploit leverages deserialization via the `VsanCapabilityProvider` endpoint to execute arbitrary commands by chaining method calls to `javax.naming.InitialContext.doLookup`.

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.

Exploits (14)

nomisec WORKING POC 215 stars
by alt3kx · remote
https://github.com/alt3kx/CVE-2021-21985_PoC

This repository provides a functional proof-of-concept exploit for CVE-2021-21985, a remote code execution vulnerability in VMware vCenter Server's Virtual SAN Health Check plug-in. The exploit leverages deserialization via the `VsanCapabilityProvider` endpoint to execute arbitrary commands by chaining method calls to `javax.naming.InitialContext.doLookup`.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter Server 6.5-7.0
No auth needed
Prerequisites: Network access to the vCenter Server · RMI server to host the malicious payload
devstral-2 · analyzed Feb 19, 2026 Full analysis →
nomisec WORKING POC 115 stars
by xnianq · remote
https://github.com/xnianq/cve-2021-21985_exp

This repository contains a functional exploit for CVE-2021-21985, a remote code execution vulnerability in VMware vCenter Server. The exploit leverages JNDI injection via the `vsanQueryUtil_setDataService` endpoint to achieve RCE by chaining method calls to execute arbitrary commands through an RMI server.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter Server (versions affected by CVE-2021-21985)
No auth needed
Prerequisites: Access to the target vCenter Server's UI endpoint · An RMI server hosting a malicious payload (e.g., JNDI-Injection-Bypass)
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 31 stars
by testanull · poc
https://github.com/testanull/Project_CVE-2021-21985_PoC

This repository contains a functional exploit for CVE-2021-21985, a remote code execution vulnerability in VMware vCenter Server. The exploit leverages JNI (Java Native Interface) to execute arbitrary commands by loading a malicious shared library.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter Server (versions affected by CVE-2021-21985)
No auth needed
Prerequisites: Network access to the vulnerable vCenter Server · Ability to upload files to the target system
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 3 stars
by sknux · poc
https://github.com/sknux/CVE-2021-21985_PoC

This repository contains a functional exploit for CVE-2021-21985, a remote code execution vulnerability in the VMware vCenter Server Virtual SAN Health Check plugin. The exploit allows unauthenticated attackers to execute commands with unrestricted privileges on the underlying OS hosting vCenter Server.

Classification
Working Poc 90%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter Server (7.x before 7.0 U2b, 6.7 before 6.7 U3n, and 6.5 before 6.5 U3p) and VMware Cloud Foundation (4.x before 4.2.1 and 3.x before 3.10.2.1)
No auth needed
Prerequisites: Network access to port 443 on the target vCenter Server
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 2 stars
by daedalus · remote
https://github.com/daedalus/CVE-2021-21985

This Python script exploits CVE-2021-21985, a remote code execution vulnerability in VMware vCenter Server 6.7-7.0. It crafts a malicious HTTP POST request targeting the `/ui/h5-vsan/rest/proxy/service/` endpoint with a serialized payload to achieve RCE via RMI deserialization.

Classification
Working Poc 90%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter Server 6.7-7.0
No auth needed
Prerequisites: Network access to the target vCenter Server · Target must be vulnerable (unpatched)
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec SCANNER 2 stars
by onSec-fr · infoleak
https://github.com/onSec-fr/CVE-2021-21985-Checker

This repository contains a PowerShell script that checks for the presence of CVE-2021-21985 by sending a crafted HTTP POST request to a VMware vCenter Server endpoint and analyzing the response. It does not exploit the vulnerability but detects its presence.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: VMware vCenter Server
No auth needed
Prerequisites: Network access to the target vCenter Server
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC 1 stars
by haidv35 · poc
https://github.com/haidv35/CVE-2021-21985

This repository contains functional exploit code for CVE-2021-21985, a vulnerability in VMware vCenter Server. The PoC demonstrates a chain of HTTP requests to achieve remote code execution (RCE) by manipulating the VsanHttpProvider and leveraging JNDI injection.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter Server (versions affected by CVE-2021-21985)
No auth needed
Prerequisites: Network access to the vulnerable vCenter Server · Python environment with required libraries (requests, urllib3)
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WRITEUP 1 stars
by bigbroke · poc
https://github.com/bigbroke/CVE-2021-21985

The repository provides a description of CVE-2021-21985, a critical RCE vulnerability in VMware vCenter Server's Virtual SAN Health Check plug-in due to lack of input validation. However, it lacks technical details, exploit code, or patch analysis, making it more of a high-level summary than a deep technical writeup.

Classification
Writeup 70%
Attack Type
Rce
Complexity
Moderate
Reliability
Theoretical
Target: VMware vCenter Server (vSphere Client HTML5)
No auth needed
Prerequisites: Network access to port 443 on vCenter Server
devstral-2 · analyzed Feb 18, 2026 Full analysis →
gitlab WORKING POC
by bybsecs · remote
https://gitlab.com/bybsecs/CVE-2021-21985

This repository contains functional exploit code for CVE-2021-21985, a vulnerability in VMware vCenter. The exploit leverages SSRF and RMI deserialization to achieve remote code execution (RCE) on the target system.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter
No auth needed
Prerequisites: Access to the target vCenter server · Network connectivity to the target
devstral-2 · analyzed Feb 23, 2026 Full analysis →
gitlab WORKING POC
by securitystuffbackup · poc
https://gitlab.com/securitystuffbackup/CVE-2021-21985_PoC

This repository provides a functional proof-of-concept exploit for CVE-2021-21985, a remote code execution vulnerability in VMware vCenter Server's Virtual SAN Health Check plug-in. The exploit leverages deserialization via the `VsanCapabilityProvider` endpoint to execute arbitrary commands by chaining method calls to achieve RCE.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter Server 6.5-7.0
No auth needed
Prerequisites: Network access to the vCenter Server · Python HTTP server to receive the RMI callback
devstral-2 · analyzed Feb 23, 2026 Full analysis →
nomisec WORKING POC
by aristosMiliaressis · poc
https://github.com/aristosMiliaressis/CVE-2021-21985

This repository contains functional exploit code for CVE-2021-21985, a deserialization vulnerability in VMware vSphere. The PoC includes scripts for both forward and reverse shell execution, leveraging malicious Spring bean definitions to achieve remote code execution.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vSphere (vCenter Server)
No auth needed
Prerequisites: Network access to the vSphere UI endpoint · Target system running vulnerable vSphere version
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec SCANNER
by mauricelambert · infoleak
https://github.com/mauricelambert/CVE-2021-21985

This script checks for the presence of CVE-2021-21985 by sending a crafted JSON payload to a specific vCenter Server endpoint and analyzing the HTTP response status and content. It does not exploit the vulnerability but detects whether the target is vulnerable or patched.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: VMware vCenter Server
No auth needed
Prerequisites: Network access to the vCenter Server · Target endpoint must be reachable
devstral-2 · analyzed Feb 18, 2026 Full analysis →
vulncheck_xdb WORKING POC
remote
https://github.com/Schira4396/VcenterKiller

This repository contains a functional exploit tool for multiple VMware vCenter vulnerabilities, including CVE-2021-21985. It provides command execution, file upload, and reverse shell capabilities, with specific modules for different CVEs.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter (versions 6.7, 7.0)
No auth needed
Prerequisites: network access to target vCenter · Go environment for compilation
devstral-2 · analyzed Feb 25, 2026 Full analysis →
metasploit WORKING POC EXCELLENT
by Ricter Z, wvu · rubypocunix
https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/http/vmware_vcenter_vsan_health_rce.rb

This Metasploit module exploits CVE-2021-21985, a vulnerability in VMware vCenter Server's Virtual SAN Health Check plugin. It leverages Java unsafe reflection and SSRF to achieve remote code execution as the vsphere-ui user by crafting a malicious data URI with a Spring bean definition.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: VMware vCenter Server 6.7 Update 3m (Linux appliance)
No auth needed
Prerequisites: Network access to the vCenter Server on port 443
devstral-2 · analyzed Feb 19, 2026 Full analysis →

Nuclei Templates (1)

VMware vSphere Client (HTML5) - Remote Code Execution
CRITICALby D0rkerDevil

Scores

CVSS v3 9.8
EPSS 0.9441
EPSS Percentile 100.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation active
Automatable yes
Technical Impact total

Details

CISA KEV 2021-11-03
VulnCheck KEV 2021-06-04
InTheWild.io 2021-06-05
ENISA EUVD EUVD-2021-9156
Ransomware Use Confirmed
CWE
CWE-470 CWE-918 CWE-20
Status published
Products (4)
vmware/cloud_foundation 3.0 - 3.10.2.1
vmware/vcenter_server 6.5 (23 CPE variants)
vmware/vcenter_server 6.7 (17 CPE variants)
vmware/vcenter_server 7.0 (9 CPE variants)
Published May 26, 2021
KEV Added Nov 03, 2021
Tracked Since Feb 18, 2026