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Vulnerabilities

Vulnerability · CVE-2021-21973

VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability

Published Feb 24, 2021 · catalog updated Jun 16, 2026 · VMware vCenter Server and Cloud Foundation

Patch now

CVE-2021-21973 is in the CISA known-exploited catalog, due Mar 21, 2022. Confirm VMware vCenter Server and Cloud Foundation against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Medium5.3
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
88.01%
Remediation
Remediation guidance
Affected products
cpe vmware/cloud foundation · cpe vmware/vcenter server · vendor VMware vCenter Server and Cloud Foundation

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).

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe vmware/cloud foundationversion unspecified
  • cpe vmware/vcenter server6.5
  • vendor VMware vCenter Server and Cloud Foundationversion unspecified

How to fix CVE-2021-21973

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-21973 is in the CISA known-exploited catalog, due Mar 21, 2022. Confirm VMware vCenter Server and Cloud Foundation against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with vmware/vcenter server 6.5. Apply updates per vendor instructions.

What should an analyst verify?

CWE-20: Improper Input Validation; CWE-918: Server-Side Request Forgery (SSRF). EPSS 88.01%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 24, 2021 · Catalog

    Detected

    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

  2. Mar 7, 2022 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Mar 21, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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

Sources

  • CISA KEVConfirmed exploitationCVE-2021-21973

    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.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-21973

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-21973

    30-day exploitation probability 88.0%

    first.org
  • NIST NVDVulnerability recordCVE-2021-21973

    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 leadi

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2021-21973

    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.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.