CVE-2021-1228

HIGHNVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under NVD CVSS v3. EPSS exploit probability: 0.4% (30th percentile of EPSS-scored CVEs). GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
7.4EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.4Exploit: None knownExposed services: Not assessed

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

A vulnerability in the fabric infrastructure VLAN connection establishment of Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode could allow an unauthenticated, adjacent attacker to bypass security validations and connect an unauthorized server to the infrastructure VLAN. This vulnerability is due to insufficient security requirements during the Link Layer Discovery Protocol (LLDP) setup phase of the infrastructure VLAN. An attacker could exploit this vulnerability by sending a crafted LLDP packet on the adjacent subnet to an affected device. A successful exploit could allow the attacker to connect an unauthorized server to the infrastructure VLAN, which is highly privileged. With a connection to the infrastructure VLAN, the attacker can make unauthorized connections to Cisco Application Policy Infrastructure Controller (APIC) services or join other host endpoints.

CVSS v3
7.4
EG Score
7.4HIGHmedium confidence
EG Risk
33
EG Risk 33/100CISA SSVC

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
Severity74% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.4%
EPSS %ILE
30th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

February 24, 2021

Last Modified

November 21, 2024

References (2)

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 30× 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 166 total refreshes for this CVE.

  1. 2026-10-03 14:22 UTCEPSS rescore
  2. 2026-10-03 14:22 UTCEPSS rescore
  3. 2026-10-02 16:22 UTCEPSS rescore
  4. 2026-10-01 19:46 UTCEPSS rescore
  5. 2026-09-30 15:27 UTCEG score recompute
  6. 2026-09-30 15:00 UTCEPSS rescore
  7. 2026-09-27 13:41 UTCEPSS rescore
  8. 2026-09-26 15:54 UTCEPSS rescore
  9. 2026-09-26 15:54 UTCEPSS rescore
  10. 2026-09-26 00:21 UTCEPSS rescore
  11. 2026-09-24 14:00 UTCEPSS rescore
  12. 2026-09-24 14:00 UTCEPSS rescore
  13. 2026-09-23 13:44 UTCEPSS rescore
  14. 2026-09-22 14:44 UTCEPSS rescore
  15. 2026-09-21 20:28 UTCEPSS rescore
  16. 2026-09-19 15:37 UTCEPSS rescore
  17. 2026-09-18 19:23 UTCEPSS rescore
  18. 2026-09-17 19:23 UTCEPSS rescore
  19. 2026-09-16 14:05 UTCEPSS rescore
  20. 2026-09-16 14:04 UTCEPSS rescore
  21. 2026-09-15 03:06 UTCEPSS rescore
  22. 2026-09-13 16:43 UTCEPSS rescore
  23. 2026-09-12 14:57 UTCEPSS rescore
  24. 2026-09-11 09:33 UTCEPSS rescore
  25. 2026-09-10 09:29 UTCEPSS rescore
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  1. 2026-09-08 21:56 UTCEPSS rescore
  2. 2026-09-07 15:58 UTCEPSS rescore
  3. 2026-09-06 13:44 UTCEPSS rescore
  4. 2026-09-06 13:44 UTCEPSS rescore
  5. 2026-09-05 15:25 UTCEPSS rescore
  6. 2026-09-04 13:57 UTCEPSS rescore
  7. 2026-09-04 05:03 UTCEPSS rescore
  8. 2026-09-02 14:08 UTCEPSS rescore
  9. 2026-09-01 13:50 UTCEPSS rescore
  10. 2026-09-01 03:32 UTCEPSS rescore
  11. 2026-08-30 19:14 UTCEPSS rescore
  12. 2026-08-30 01:19 UTCEPSS rescore
  13. 2026-08-28 21:37 UTCEPSS rescore
  14. 2026-08-27 14:22 UTCEPSS rescore
  15. 2026-08-26 14:42 UTCEPSS rescore
  16. 2026-08-25 13:45 UTCEPSS rescore
  17. 2026-08-23 00:16 UTCEPSS rescore
  18. 2026-08-21 23:46 UTCEPSS rescore
  19. 2026-08-20 22:52 UTCEPSS rescore
  20. 2026-08-19 17:01 UTCEPSS rescore
  21. 2026-08-18 13:45 UTCEPSS rescore
  22. 2026-08-17 13:43 UTCEPSS rescore
  23. 2026-08-16 14:52 UTCEPSS rescore
  24. 2026-08-16 02:11 UTCEPSS rescore
  25. 2026-08-15 01:27 UTCEPSS rescore
  26. 2026-08-13 21:57 UTCEPSS rescore
  27. 2026-08-12 13:47 UTCEPSS rescore
  28. 2026-08-11 13:38 UTCEPSS rescore
  29. 2026-08-09 13:43 UTCEPSS rescore
  30. 2026-08-08 16:33 UTCEPSS rescore
  31. 2026-08-07 16:23 UTCEPSS rescore
  32. 2026-08-06 13:43 UTCEPSS rescore
  33. 2026-08-05 19:14 UTCEPSS rescore
  34. 2026-08-04 15:06 UTCEPSS rescore
  35. 2026-08-04 10:34 UTCEPSS rescore
  36. 2026-08-03 10:32 UTCEPSS rescore
  37. 2026-08-02 02:24 UTCEPSS rescore
  38. 2026-08-01 04:12 UTCEPSS rescore
  39. 2026-07-30 16:25 UTCEPSS rescore
  40. 2026-07-30 01:27 UTCEPSS rescore
  41. 2026-07-30 01:27 UTCEPSS rescore
  42. 2026-07-26 14:52 UTCEPSS rescore
  43. 2026-07-25 14:15 UTCEPSS rescore
  44. 2026-07-24 14:15 UTCEPSS rescore
  45. 2026-07-23 14:15 UTCEPSS rescore
  46. 2026-07-23 01:56 UTCEG score recompute
  47. 2026-07-22 22:42 UTCEG score recompute▲ 0.90
  48. 2026-07-22 14:05 UTCEPSS rescore
  49. 2026-07-21 15:22 UTCEPSS rescore
  50. 2026-07-21 15:22 UTCEPSS rescore
  51. 2026-07-20 17:04 UTCEPSS rescore
  52. 2026-07-19 14:28 UTCEPSS rescore
  53. 2026-07-19 02:26 UTCEPSS rescore
  54. 2026-07-18 10:02 UTCEPSS rescore
  55. 2026-07-16 17:00 UTCEPSS rescore
  56. 2026-07-15 16:55 UTCEPSS rescore
  57. 2026-07-15 16:55 UTCEPSS rescore
  58. 2026-07-15 01:57 UTCEPSS rescore
  59. 2026-07-13 22:27 UTCEPSS rescore
  60. 2026-07-13 22:27 UTCEPSS rescore
  61. 2026-07-13 06:10 UTCEPSS rescore
  62. 2026-07-13 06:10 UTCEPSS rescore
  63. 2026-07-12 05:44 UTCEPSS rescore
  64. 2026-07-12 05:44 UTCEPSS rescore
  65. 2026-07-11 08:25 UTCEPSS rescore
  66. 2026-07-09 19:07 UTCEPSS rescore
  67. 2026-07-08 15:12 UTCEPSS rescore
  68. 2026-07-07 13:43 UTCEPSS rescore
  69. 2026-07-06 16:25 UTCEPSS rescore
  70. 2026-07-06 02:21 UTCEPSS rescore
  71. 2026-07-06 02:21 UTCEPSS rescore
  72. 2026-07-05 02:28 UTCEPSS rescore
  73. 2026-07-05 02:28 UTCEPSS rescore
  74. 2026-07-04 06:29 UTCEPSS rescore
  75. 2026-07-04 06:29 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2021-1228?
CVE-2021-1228 is a high vulnerability published on February 24, 2021. A vulnerability in the fabric infrastructure VLAN connection establishment of Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode could allow an unauthenticated, adjacent attacker to bypass security validations and connect an unauthorized server to the…
When was CVE-2021-1228 disclosed?
CVE-2021-1228 was first published on February 24, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-1228 actively exploited?
CVE-2021-1228 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (30th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-1228?
CVE-2021-1228 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2021-1228?
No fix for CVE-2021-1228 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix.

Dependency Blast Radius

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