CVE-2021-3523

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-04-28. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.5Exploit: NoneExposed: 0

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

A flaw was found in 3Scale APICast in versions prior to 2.11.0, where it incorrectly identified connections for reuse. This flaw allows an attacker to bypass security restrictions for an API request when hosting multiple APIs on the same IP address.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
53.3%
KEV
Not listed

Published

April 27, 2022

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 10× in last 7d / 46× 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 102 total refreshes for this CVE.

  1. 2026-07-22 14:06 UTCEPSS rescore
  2. 2026-07-21 15:22 UTCEPSS rescore
  3. 2026-07-21 15:22 UTCEPSS rescore
  4. 2026-07-20 17:05 UTCEPSS rescore
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  21. 2026-07-09 19:07 UTCEPSS rescore
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  1. 2026-07-06 02:21 UTCEPSS rescore
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  5. 2026-07-04 06:29 UTCEPSS rescore
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  7. 2026-07-02 16:57 UTCEPSS rescore
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  9. 2026-06-30 23:20 UTCEPSS rescore
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  11. 2026-06-28 14:05 UTCEPSS rescore
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  20. 2026-06-23 21:31 UTCEPSS rescore
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  22. 2026-06-22 14:24 UTCEPSS rescore
  23. 2026-06-21 14:55 UTCEPSS rescore
  24. 2026-06-21 01:58 UTCEPSS rescore
  25. 2026-06-21 01:58 UTCEPSS rescore
  26. 2026-06-19 19:24 UTCEPSS rescore
  27. 2026-06-19 19:24 UTCEPSS rescore
  28. 2026-06-18 17:51 UTCEPSS rescore
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  40. 2026-06-12 23:10 UTCEPSS rescore
  41. 2026-06-11 13:58 UTCEPSS rescore
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  43. 2026-06-10 22:16 UTCEPSS rescore
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  45. 2026-06-10 13:20 UTCEPSS rescore
  46. 2026-06-08 14:15 UTCEPSS rescore
  47. 2026-06-08 14:15 UTCEPSS rescore
  48. 2026-06-07 15:23 UTCEPSS rescore
  49. 2026-06-07 15:23 UTCEPSS rescore
  50. 2026-06-06 13:46 UTCEPSS rescore
  51. 2026-06-06 13:46 UTCEPSS rescore
  52. 2026-06-05 22:45 UTCEPSS rescore
  53. 2026-06-05 06:09 UTCEPSS rescore
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  55. 2026-06-04 13:10 UTCEPSS rescore
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  65. 2026-05-29 13:42 UTCEPSS rescore
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  67. 2026-05-28 13:43 UTCEPSS rescore
  68. 2026-05-27 13:39 UTCEPSS rescore
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  72. 2026-05-26 07:17 UTCEPSS rescore
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  74. 2026-05-26 07:17 UTCEPSS rescore
  75. 2026-05-25 23:06 UTCEG score recompute

Frequently asked(5)

What is CVE-2021-3523?
CVE-2021-3523 is a high vulnerability published on April 27, 2022. A flaw was found in 3Scale APICast in versions prior to 2.11.0, where it incorrectly identified connections for reuse. This flaw allows an attacker to bypass security restrictions for an API request when hosting multiple APIs on the same IP address.
When was CVE-2021-3523 disclosed?
CVE-2021-3523 was first published in the National Vulnerability Database on April 27, 2022, 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-2021-3523 actively exploited?
CVE-2021-3523 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 53.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-3523?
CVE-2021-3523 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2021-3523?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3523, 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.

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