CVE-2021-21973: VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability
Reference page built from the source records below, each shown as its source publishes it. Dataset version ref-7ffec48701f4, updated 2026-11-02T23:39:54.475Z.
CISA Known Exploited Vulnerabilities
- Name
- VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability
- Vendor
- VMware
- Product
- vCenter Server and Cloud Foundation
- Added to the catalog
- 2022-03-07
- Due date for US federal agencies
- 2022-03-21
- Weaknesses
- CWE-20, CWE-918
- Catalog version
- 2026.10.30
VMware vCenter Server and Cloud Foundation Server contain a SSRF vulnerability due to improper validation of URLs in a vCenter Server plugin. This allows for information disclosure.
Required action (CISA)
Apply updates per vendor instructions.
Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.
Links in CISA's notes
Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
NVD analysis
- Status
- Analyzed
- Published
- 2021-02-24T17:15:15.923
- Last modified
- 2026-06-17T03:36:28.910
- Weaknesses
- CWE-918
The vSphere Client (HTML5) contains an SSRF (Server Side Request Forgery) vulnerability due to improper validation of URLs in a vCenter Server plugin. A malicious actor with network access to port 443 may exploit this issue by sending a POST request to vCenter Server plugin leading to information disclosure. This affects: VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).
| Metric | Score | Severity | Vector | Scored by |
|---|---|---|---|---|
| CVSS 3.1 | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | [email protected] (Primary) |
| CVSS 3.1 | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
| CVSS 2.0 | 5 | MEDIUM | AV:N/AC:L/Au:N/C:P/I:N/A:N | [email protected] (Primary) |
References
- https://www.vmware.com/security/advisories/VMSA-2021-0002.html (Vendor Advisory)
- https://www.vmware.com/security/advisories/VMSA-2021-0002.html (Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21973 (US Government Resource)
This product uses the NVD API but is not endorsed or certified by the NVD.
Read on 2026-11-02T23:41:51.476Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2021-21973
CVE record
- Assigner
- vmware
- State
- PUBLISHED
- Published
- 2021-02-24T16:42:02.000Z
- Updated
- 2025-10-21T23:25:54.167Z
- Problem types
- SSRF vulnerability
The vSphere Client (HTML5) contains an SSRF (Server Side Request Forgery) vulnerability due to improper validation of URLs in a vCenter Server plugin. A malicious actor with network access to port 443 may exploit this issue by sending a POST request to vCenter Server plugin leading to information disclosure. This affects: VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).
References
Read on 2026-11-03T01:06:06.476Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2021/21xxx/CVE-2021-21973.json
Defensive techniques (MITRE D3FEND)
D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.
CWE-918: Server-Side Request Forgery (SSRF)
- Isolate: Application-based Process Isolation (acts on Subroutine)
- Restore: Restore Software (acts on Software)
- Model: Asset Vulnerability Enumeration (acts on Software)
- Harden: Trusted Library (acts on Subroutine)
- Harden: Domain Logic Validation (acts on Subroutine)
- Harden: Variable Initialization (acts on Subroutine)
- Harden: Credential Scrubbing (acts on Subroutine)
- Harden: Software Update (acts on Software)
- Model: Software Inventory (acts on Software)
D3FEND ontology version 1.6.0.
Read on 2026-11-03T00:03:22.605Z under licence d3fend-terms-of-use@f98cbc7e from https://d3fend.mitre.org/api/weakness/cwe/CWE-918.json
MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/
Sources and licences
CISA
Source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30, CC0 1.0. Use of this data does not imply endorsement by CISA or DHS.
National Vulnerability Database (NIST)
This product uses the NVD API but is not endorsed or certified by the NVD.
NVD API Terms of Use (NIST publications in the public domain, 17 U.S.C. 105)
CVE Program, The MITRE Corporation
Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation. CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
MITRE D3FEND
MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/MITRE D3FEND Terms of Use (site + knowledge graph); source repo MIT
Cite this page
Dragons Eye Ransomware Tracker, "CVE-2021-21973: VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability",
entity page, dataset version ref-7ffec48701f4, updated 2026-11-02T23:39:54.475Z,
https://ransomware-tracker.com/cve/CVE-2021-21973 (accessed 2026-11-03).
Underlying source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30.
Underlying source: National Vulnerability Database (NIST), CVE API 2.0, record last modified 2026-06-17T03:36:28.910.
Underlying source: CVE List (CVE Program, The MITRE Corporation), record updated 2025-10-21T23:25:54.167Z.
Underlying source: MITRE D3FEND, ontology version 1.6.0.
Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.