CVE-2021-34740

HIGHNVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

Score 7.4 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 7.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.4
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.4Exploit: NoneExposed: 0

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

A vulnerability in the WLAN Control Protocol (WCP) implementation for Cisco Aironet Access Point (AP) software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to incorrect error handling when an affected device receives an unexpected 802.11 frame. An attacker could exploit this vulnerability by sending certain 802.11 frames over the wireless network to an interface on an affected AP. A successful exploit could allow the attacker to cause a packet buffer leak. This could eventually result in buffer allocation failures, which would trigger a reload of the affected device.

CVSS v3
7.4
EG Score
7.4(medium)
EG Risk
33(Track)
EG Risk 33/100SSVC: 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
Severity74% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
28.5%
KEV
Not listed

Published

September 23, 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 14× in last 7d / 47× 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 101 total refreshes for this CVE.

  1. 2026-07-23 14:16 UTCEPSS rescore
  2. 2026-07-23 14:16 UTCEPSS rescore
  3. 2026-07-23 02:01 UTCEG score recompute
  4. 2026-07-22 22:48 UTCEG score recompute
  5. 2026-07-22 14:06 UTCEPSS rescore
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  7. 2026-07-21 15:22 UTCEPSS rescore
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  25. 2026-07-09 19:07 UTCEPSS rescore
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  1. 2026-07-08 15:12 UTCEPSS rescore
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  21. 2026-06-23 21:31 UTCEPSS rescore
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  23. 2026-06-22 14:24 UTCEPSS rescore
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  25. 2026-06-21 14:55 UTCEPSS rescore
  26. 2026-06-21 01:58 UTCEPSS rescore
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  28. 2026-06-19 19:24 UTCEPSS rescore
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  30. 2026-06-18 17:51 UTCEPSS rescore
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  39. 2026-06-12 23:10 UTCEPSS rescore
  40. 2026-06-12 23:10 UTCEPSS rescore
  41. 2026-06-11 13:58 UTCEPSS rescore
  42. 2026-06-10 22:16 UTCEPSS rescore
  43. 2026-06-10 13:20 UTCEPSS rescore
  44. 2026-06-08 14:15 UTCEPSS rescore
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  46. 2026-06-07 15:23 UTCEPSS rescore
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  48. 2026-06-06 13:46 UTCEPSS rescore
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  51. 2026-06-05 22:45 UTCEPSS rescore
  52. 2026-06-05 06:09 UTCEPSS rescore
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  54. 2026-06-04 13:10 UTCEPSS rescore
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  58. 2026-06-01 13:50 UTCEPSS rescore
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  68. 2026-05-27 13:39 UTCEPSS rescore
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  71. 2026-05-26 13:42 UTCEPSS rescore
  72. 2026-05-26 10:01 UTCEG score recompute
  73. 2026-05-26 10:01 UTCGHSA enrichment
  74. 2026-05-26 07:17 UTCEPSS rescore
  75. 2026-05-26 07:17 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2021-34740?
CVE-2021-34740 is a high vulnerability published on September 23, 2021. A vulnerability in the WLAN Control Protocol (WCP) implementation for Cisco Aironet Access Point (AP) software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to incorrect error…
When was CVE-2021-34740 disclosed?
CVE-2021-34740 was first published in the National Vulnerability Database on September 23, 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-2021-34740 actively exploited?
CVE-2021-34740 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 28.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-34740?
CVE-2021-34740 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2021-34740?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-34740, 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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