Exploited CVEs / VMware / CVE-2021-21973
CVE-2021-21973
VMware vCenter Server and Cloud Foundation Server Side Request Forgery (SSRF) Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2022-03-21 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Broadcom (VMware) Security Advisories, linked below.
Actively exploited VMware vCenter Server and Cloud Foundation vulnerability, Medium severity, CVSS 5.3. Added to the CISA KEV catalog 2022-03-07.
Risk summary
Updated July 28, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2021-21973
An SSRF flaw in a vCenter Server plugin lets attackers make the server issue requests on their behalf, disclosing information useful for mapping the virtualization environment. The CVSS score is only 5.3, Medium Severity, yet the 88% EPSS probability and KEV listing show attackers use it in practice, usually as reconnaissance ahead of more damaging vCenter attacks. vCenter's position managing the hypervisor estate means even information leaks matter.
Do this: Confirm vCenter is patched and unreachable from the internet, restricting management-plane access to a dedicated admin network.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2021-21973
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2021-21973
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2022-03-21 (past due).
Apply updates per vendor instructions.
Official fix for CVE-2021-21973
The authoritative fix and affected-version list are published by the vendor. Find the vCenter Server and Cloud Foundation advisory on Broadcom (VMware) Security Advisories.
Common questions about CVE-2021-21973
Is CVE-2021-21973 actively exploited?
Yes. CVE-2021-21973 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2022-03-07, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 88%.
What is the CISA deadline and required action for CVE-2021-21973?
CISA set the federal (BOD 22-01) remediation due date at 2022-03-21, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.
What fixes CVE-2021-21973?
The authoritative fix is in the vendor advisory: see Broadcom (VMware) Security Advisories for the patched vCenter Server and Cloud Foundation versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2021-21973?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2021-21973's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
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Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.
