CVE-2020-4006
CVE-2020-4006 is a security flaw in VMware products, VMware’s software for running virtual machines in data centres. Attackers can run commands on VMware products. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 3 Nov 2021.[1]
VMware products is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. VMware has published a fix or advice.
Description
CISA calls it a multiple VMware products command injection in VMware Multiple Products. In its words: “VMware Workspace One Access, Access Connector, Identity Manager, and Identity Manager Connector contain a command injection vulnerability. An attacker with network access to the administrative configurator on port 8443 and a valid password for the configurator administrator account can execute commands with unrestricted privileges on the underlying operating system.”[1]
The underlying weakness is OS command injection (CWE-78), in MITRE’s list of common software weaknesses.[2]
It scores 9.1 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; VMware’s advisory has them[3]. CISA names the product as VMware Multiple Products.
Most families won’t have VMware products; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 3 Nov 2021, 345 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 3 May 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 17%. That’s in the top 3% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
VMware has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.VMware products is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 3 May 2022 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.1.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 17%.[4] |
See also
Other VMware products flaws
- CVE-2022-22960: privilege escalation ·
- CVE-2020-3950: privilege escalation ·
Other VMware flaws
- CVE-2025-22226, VMware ESXi, Workstation, and Fusion: information disclosure ·
- CVE-2025-22225, VMware ESXi: arbitrary write ·
- CVE-2025-22224, VMware ESXi and Workstation: TOCTOU race condition ·
- CVE-2024-38813, VMware vCenter Server: privilege escalation ·
- CVE-2024-38812, VMware vCenter Server: heap-based buffer overflow ·
Other OS command injection flaws
- CVE-2026-110447, Collabora Online – Built-in CODE Server: online – built-in CODE server OS command injection ·
- CVE-2026-106931, EG Secure Solutions SiteGuard Server Edition: OS command injection ·
- CVE-2026-83549, SonicWall SMA1000 Appliances: OS command injection ·
- CVE-2026-49869, Kestra OSS: OSS OS command injection ·
- CVE-2026-73570, Synacor Zimbra Collaboration Suite (ZCS): OS command injection ·
Added the same day
- CVE-2021-42258, BQE BillQuick Web Suite: SQL injection ·
- CVE-2021-42013, Apache HTTP Server: path traversal ·
- CVE-2021-41773, Apache HTTP Server: path traversal ·
- CVE-2021-40539, Zoho ManageEngine: aDSelfService plus authentication bypass ·
- CVE-2021-40444, Microsoft MSHTML: remote code execution ·
Every VMware flaw on CISA’s list · Everything added in November 2021
References
- ^ Cybersecurity and Infrastructure Security Agency. “Multiple VMware Products Command Injection Vulnerability”. Known Exploited Vulnerabilities Catalog, added 3 Nov 2021.
- ^ National Institute of Standards and Technology. “CVE-2020-4006 Detail”. National Vulnerability Database, published 23 Nov 2020.
- ^ VMware. Advisories and fixes: vmware.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.173, percentile 97.1, 31 Oct 2026.
- CVE Program. “CVE-2020-4006”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.