CVE-2021-1388

CRITICALNVD 10.010.0—
EchelonGraph scoreMEDIUM confidence

Score 10.0 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 10.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
10.0
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 14%CVSS: 10.0Exploit: NoneExposed: 0

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

A vulnerability in an API endpoint of Cisco ACI Multi-Site Orchestrator (MSO) installed on the Application Services Engine could allow an unauthenticated, remote attacker to bypass authentication on an affected device. The vulnerability is due to improper token validation on a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted request to the affected API. A successful exploit could allow the attacker to receive a token with administrator-level privileges that could be used to authenticate to the API on affected MSO and managed Cisco Application Policy Infrastructure Controller (APIC) devices.

CVSS v3
10.0
EG Score
10.0(medium)
EG Risk
76(Track)
EG Risk 76/100SSVC: Track

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
Severity100% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
96.2%
KEV
Not listed

Published

February 24, 2021

Last Modified

November 21, 2024

Advisory Details (1)

Auto-updated Jul 18, 2026
No patch confirmed yet.
generic

Cisco ACI Multi-Site Orchestrator Application Services Engine Deployment Authentication Bypass Vulnerability

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-mso-authbyp-bb5GmBQv

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 37× 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.

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

Frequently asked(5)

What is CVE-2021-1388?
CVE-2021-1388 is a critical vulnerability published on February 24, 2021. A vulnerability in an API endpoint of Cisco ACI Multi-Site Orchestrator (MSO) installed on the Application Services Engine could allow an unauthenticated, remote attacker to bypass authentication on an affected device. The vulnerability is due to improper token validation on a specific API…
When was CVE-2021-1388 disclosed?
CVE-2021-1388 was first published in the National Vulnerability Database 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-2021-1388 actively exploited?
CVE-2021-1388 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 96.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-1388?
CVE-2021-1388 has a CVSS v3 base score of 10.0 (NVD).
How do I remediate CVE-2021-1388?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-1388, 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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