CVE-2021-21985

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score elevated to 9.8 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 3 sources updated this weekExploited in the wild
9.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 100%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EPSS
100.0%
KEV
⚠ Exploited

Published

May 26, 2021

Last Modified

October 30, 2025

Advisory Details (4)

Auto-updated Jun 1, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21985
generic

Support Content Notification - Support Portal - Broadcom support portal

https://www.vmware.com/security/advisories/VMSA-2021-0010.html
generic

Packet Storm

http://packetstormsecurity.com/files/163487/VMware-vCenter-Server-Virtual-SAN-Health-Check-Remote-Code-Execution.html
generic

Packet Storm

http://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.html

Weakness Classification(3)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 91× in last 7d / 394× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 555 total refreshes for this CVE.

  1. 2026-07-12 00:47 UTCEG score recompute
  2. 2026-07-12 00:47 UTCGHSA enrichment
  3. 2026-07-11 21:03 UTCEG score recompute
  4. 2026-07-11 21:03 UTCGHSA enrichment
  5. 2026-07-11 17:19 UTCEG score recompute
  6. 2026-07-11 17:19 UTCGHSA enrichment
  7. 2026-07-11 13:35 UTCEG score recompute
  8. 2026-07-11 13:35 UTCGHSA enrichment
  9. 2026-07-11 09:50 UTCEG score recompute
  10. 2026-07-11 09:50 UTCGHSA enrichment
  11. 2026-07-11 06:06 UTCEG score recompute
  12. 2026-07-11 06:06 UTCGHSA enrichment
  13. 2026-07-11 02:20 UTCEG score recompute
  14. 2026-07-11 02:20 UTCGHSA enrichment
  15. 2026-07-10 22:36 UTCEG score recompute
  16. 2026-07-10 22:35 UTCGHSA enrichment
  17. 2026-07-10 18:50 UTCEG score recompute
  18. 2026-07-10 18:50 UTCGHSA enrichment
  19. 2026-07-10 17:52 UTCCISA KEV update
  20. 2026-07-10 15:06 UTCEG score recompute
  21. 2026-07-10 15:06 UTCGHSA enrichment
  22. 2026-07-10 11:20 UTCEG score recompute
  23. 2026-07-10 11:20 UTCGHSA enrichment
  24. 2026-07-10 07:36 UTCEG score recompute
  25. 2026-07-10 07:35 UTCGHSA enrichment
Show 75 more
  1. 2026-07-10 03:50 UTCEG score recompute
  2. 2026-07-10 03:50 UTCGHSA enrichment
  3. 2026-07-10 00:05 UTCEG score recompute
  4. 2026-07-10 00:05 UTCGHSA enrichment
  5. 2026-07-09 20:20 UTCEG score recompute
  6. 2026-07-09 20:20 UTCGHSA enrichment
  7. 2026-07-09 16:36 UTCEG score recompute
  8. 2026-07-09 16:35 UTCGHSA enrichment
  9. 2026-07-09 12:51 UTCEG score recompute
  10. 2026-07-09 12:51 UTCGHSA enrichment
  11. 2026-07-09 09:05 UTCEG score recompute
  12. 2026-07-09 09:05 UTCGHSA enrichment
  13. 2026-07-09 05:21 UTCEG score recompute
  14. 2026-07-09 05:20 UTCGHSA enrichment
  15. 2026-07-09 01:35 UTCEG score recompute
  16. 2026-07-09 01:35 UTCGHSA enrichment
  17. 2026-07-08 21:49 UTCEG score recompute
  18. 2026-07-08 21:49 UTCGHSA enrichment
  19. 2026-07-08 18:05 UTCEG score recompute
  20. 2026-07-08 18:05 UTCGHSA enrichment
  21. 2026-07-08 14:21 UTCEG score recompute
  22. 2026-07-08 14:21 UTCGHSA enrichment
  23. 2026-07-08 10:35 UTCEG score recompute
  24. 2026-07-08 10:35 UTCGHSA enrichment
  25. 2026-07-08 06:50 UTCEG score recompute
  26. 2026-07-08 06:50 UTCGHSA enrichment
  27. 2026-07-08 03:06 UTCEG score recompute
  28. 2026-07-08 03:05 UTCGHSA enrichment
  29. 2026-07-07 23:21 UTCEG score recompute
  30. 2026-07-07 23:20 UTCGHSA enrichment
  31. 2026-07-07 19:37 UTCEG score recompute
  32. 2026-07-07 19:37 UTCGHSA enrichment
  33. 2026-07-07 19:01 UTCCISA KEV update
  34. 2026-07-07 17:16 UTCCISA KEV update
  35. 2026-07-07 15:53 UTCEG score recompute
  36. 2026-07-07 15:53 UTCGHSA enrichment
  37. 2026-07-07 12:08 UTCEG score recompute
  38. 2026-07-07 12:08 UTCGHSA enrichment
  39. 2026-07-07 08:21 UTCEG score recompute
  40. 2026-07-07 08:21 UTCGHSA enrichment
  41. 2026-07-07 04:37 UTCEG score recompute
  42. 2026-07-07 04:37 UTCGHSA enrichment
  43. 2026-07-07 00:52 UTCEG score recompute
  44. 2026-07-07 00:52 UTCGHSA enrichment
  45. 2026-07-06 21:07 UTCEG score recompute
  46. 2026-07-06 21:07 UTCGHSA enrichment
  47. 2026-07-06 17:22 UTCEG score recompute
  48. 2026-07-06 17:22 UTCGHSA enrichment
  49. 2026-07-06 13:36 UTCEG score recompute
  50. 2026-07-06 13:35 UTCGHSA enrichment
  51. 2026-07-06 09:52 UTCEG score recompute
  52. 2026-07-06 09:51 UTCGHSA enrichment
  53. 2026-07-06 06:07 UTCEG score recompute
  54. 2026-07-06 06:06 UTCGHSA enrichment
  55. 2026-07-06 02:20 UTCEG score recompute
  56. 2026-07-06 02:20 UTCGHSA enrichment
  57. 2026-07-05 22:36 UTCEG score recompute
  58. 2026-07-05 22:36 UTCGHSA enrichment
  59. 2026-07-05 18:52 UTCEG score recompute
  60. 2026-07-05 18:52 UTCGHSA enrichment
  61. 2026-07-05 15:07 UTCEG score recompute
  62. 2026-07-05 15:07 UTCGHSA enrichment
  63. 2026-07-05 11:23 UTCEG score recompute
  64. 2026-07-05 11:23 UTCGHSA enrichment
  65. 2026-07-05 07:39 UTCEG score recompute
  66. 2026-07-05 07:39 UTCGHSA enrichment
  67. 2026-07-05 03:55 UTCEG score recompute
  68. 2026-07-05 03:55 UTCGHSA enrichment
  69. 2026-07-05 00:09 UTCEG score recompute
  70. 2026-07-05 00:09 UTCGHSA enrichment
  71. 2026-07-04 20:23 UTCEG score recompute
  72. 2026-07-04 20:23 UTCGHSA enrichment
  73. 2026-07-04 16:39 UTCEG score recompute
  74. 2026-07-04 16:39 UTCGHSA enrichment
  75. 2026-07-04 12:53 UTCEG score recompute

Publicly available exploits

(8 references)

Working exploit code is in the public domain (1 Metasploit module) (6 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCsknux/CVE-2021-21985_PoC
    First seen Nov 9, 2021

    VMWARE VCENTER SERVER VIRTUAL SAN HEALTH CHECK PLUG-IN RCE (CVE-2021-21985)

    Open source ↗
  • GitHub PoCtestanull/Project_CVE-2021-21985_PoC
    First seen Jun 5, 2021
    Open source ↗
  • GitHub PoCdaedalus/CVE-2021-21985
    First seen Jun 4, 2021

    CVE-2021-21985 vmware 6.7-9.8 RCE

    Open source ↗
  • GitHub PoCxnianq/cve-2021-21985_exp
    First seen Jun 3, 2021

    cve-2021-21985 exploit

    Open source ↗
  • GitHub PoConSec-fr/CVE-2021-21985-Checker
    First seen Jun 1, 2021

    CVE-2021-21985 Checker.

    Open source ↗
  • GitHub PoCalt3kx/CVE-2021-21985_PoC
    First seen May 29, 2021
    Open source ↗
  • Metasploitexploit/linux/http/vmware_vcenter_vsan_health_rce✓ verified
    First seen May 25, 2021

    VMware vCenter Server Virtual SAN Health Check Plugin RCE

    Open source ↗
  • Nucleihttp/cves/2021/CVE-2021-21985.yaml
    First seen Jan 1, 2021

    VMware vSphere Client (HTML5) - Remote Code Execution

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2021-21985?
CVE-2021-21985 is a critical vulnerability published on May 26, 2021. 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…
When was CVE-2021-21985 disclosed?
CVE-2021-21985 was first published in the National Vulnerability Database on May 26, 2021, with the most recent update on October 30, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-21985 actively exploited?
Yes. CISA added CVE-2021-21985 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting VMware vCenter Server. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-21985?
CVE-2021-21985 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2021-21985?
CVE-2021-21985 affects VMware vCenter Server. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-21985?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-21985, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2021-21985

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