# CVE-2021-21985: VMware vCenter Server Improper Input Validation

> Remote attackers can execute arbitrary commands with unrestricted privileges on the vCenter Server host via the Virtual SAN Health Check plug-in.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 3 Nov 2021 (CISA KEV), used in ransomware
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 May 2021
- **Updated:** 12 Aug 2026
- **Also known as:** GHSA-rg6m-2r9v-c5fj

## What is CVE-2021-21985?

CVE-2021-21985 is a critical command injection vulnerability in Vmware Cloud Foundation, published on 26 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-470 (Use of Externally-Controlled Input to Select Classes or Code), CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2021-21985?

It affects 2 products.


Products: Vmware Cloud Foundation, Vmware Vcenter Server.

## How do I fix CVE-2021-21985?

No fix has been published for CVE-2021-21985 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 17 Nov 2021.

## Is CVE-2021-21985 being exploited?

Yes. Attackers have exploited CVE-2021-21985 in the wild since at least 3 Nov 2021, including in ransomware campaigns.

Public exploit code:

- https://github.com/alt3kx/CVE-2021-21985_PoC (github_poc): https://github.com/alt3kx/CVE-2021-21985_PoC
- cve-2021-21985 exploit (github_poc): https://github.com/xnianq/cve-2021-21985_exp
- https://github.com/testanull/Project_CVE-2021-21985_PoC (github_poc): https://github.com/testanull/Project_CVE-2021-21985_PoC
- VMWARE VCENTER SERVER VIRTUAL SAN HEALTH CHECK PLUG-IN RCE (CVE-2021-21985)  (github_poc): https://github.com/sknux/CVE-2021-21985_PoC
- CVE-2021-21985 Checker. (github_poc): https://github.com/onSec-fr/CVE-2021-21985-Checker
- CVE-2021-21985 vmware 6.7-9.8 RCE (github_poc): https://github.com/daedalus/CVE-2021-21985

## Other vulnerabilities in Vmware Cloud Foundation

- [CVE-2024-38812](https://insights.sbomify.com/CVE-2024-38812/): VMware vCenter Server Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-37079](https://insights.sbomify.com/CVE-2024-37079/): Broadcom VMware vCenter Server Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2022-22954](https://insights.sbomify.com/CVE-2022-22954/): VMware Workspace ONE Access and Identity Manager Server-Side Template Injection (critical 9.8, exploited in the wild)
- [CVE-2021-22005](https://insights.sbomify.com/CVE-2021-22005/): VMware vCenter Server File Upload (critical 9.8, exploited in the wild)
- [CVE-2021-21975](https://insights.sbomify.com/CVE-2021-21975/): VMware Server Side Request Forgery in vRealize Operations Manager API (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21985 and fix it if it is affected.

What it is: CVE-2021-21985 is a critical command injection vulnerability in Vmware Cloud Foundation, published on 26 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2021-21985 in the wild since at least 3 Nov 2021, including in ransomware campaigns.

Affected product: Vmware Cloud Foundation. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-21985/ (Markdown: https://insights.sbomify.com/CVE-2021-21985/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21985
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21985
- OSV: https://osv.dev/vulnerability/CVE-2021-21985

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21985/
Summaries are generated and may contain mistakes; the official description above is the record.