CVE-2021-22017

CRITICALNVD 5.39.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2022-01-10), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 5.3 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 49%CVSS: 5.3Exploit: cisa kev · ssvc active · epss top5pct · public exploitExposed: 0

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

Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed.

CVSS v3
5.3
EG Score
9.0(high)
EG Risk
96(Attend)
EG Risk 96/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
49%
EPSS %ILE
99%
KEV
⚠ Exploited

Published

September 23, 2021

Last Modified

October 30, 2025

Advisory Details (2)

Auto-updated Jun 13, 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-2021-22017
generic🔴 Active Exploitation

Support Content Notification - Support Portal - Broadcom support portal

https://www.vmware.com/security/advisories/VMSA-2021-0020.html

Data Freshness Timeline

(refreshed 58× in last 7d / 250× 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 817 total refreshes for this CVE.

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

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleihttp/cves/2021/CVE-2021-22017.yaml
    First seen Jan 1, 2021

    vCenter Server - Improper Access Control

    Open source ↗

Frequently asked(6)

What is CVE-2021-22017?
CVE-2021-22017 is a critical vulnerability published on September 23, 2021. Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed.
When was CVE-2021-22017 disclosed?
CVE-2021-22017 was first published in the National Vulnerability Database on September 23, 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-2021-22017 actively exploited?
Yes. CISA added CVE-2021-22017 to the Known Exploited Vulnerabilities catalog on January 10, 2022, 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-2021-22017?
CVE-2021-22017 has a CVSS v3 base score of 5.3 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2021-22017?
CVE-2021-22017 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-2021-22017?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-22017, 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

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