CVE-2021-34741

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. 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 vulnerability in the email scanning algorithm of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to perform a denial of service (DoS) attack against an affected device. This vulnerability is due to insufficient input validation of incoming emails. An attacker could exploit this vulnerability by sending a crafted email through Cisco ESA. A successful exploit could allow the attacker to exhaust all the available CPU resources on an affected device for an extended period of time, preventing other emails from being processed and resulting in a DoS condition.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
66.1%
KEV
Not listed

Published

November 4, 2021

Last Modified

November 21, 2024

References (2)

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 41× 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. 2026-07-21 15:22 UTCEPSS rescore
  2. 2026-07-21 15:22 UTCEPSS rescore
  3. 2026-07-20 17:05 UTCEPSS rescore
  4. 2026-07-19 02:27 UTCEPSS rescore
  5. 2026-07-18 10:02 UTCEPSS rescore
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  10. 2026-07-15 01:58 UTCEPSS rescore
  11. 2026-07-13 22:27 UTCEPSS rescore
  12. 2026-07-13 06:10 UTCEPSS rescore
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  15. 2026-07-11 08:25 UTCEPSS rescore
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  17. 2026-07-09 19:07 UTCEPSS rescore
  18. 2026-07-08 15:12 UTCEPSS rescore
  19. 2026-07-07 13:43 UTCEPSS rescore
  20. 2026-07-06 16:25 UTCEPSS rescore
  21. 2026-07-06 02:21 UTCEPSS rescore
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  1. 2026-07-01 15:04 UTCEPSS rescore
  2. 2026-06-30 23:20 UTCEPSS rescore
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  5. 2026-06-28 14:05 UTCEPSS rescore
  6. 2026-06-28 04:54 UTCEPSS rescore
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  8. 2026-06-27 03:06 UTCEPSS rescore
  9. 2026-06-25 13:48 UTCEPSS rescore
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  11. 2026-06-24 14:03 UTCEPSS rescore
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  17. 2026-06-21 14:55 UTCEPSS rescore
  18. 2026-06-21 01:58 UTCEPSS rescore
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  20. 2026-06-19 19:24 UTCEPSS rescore
  21. 2026-06-19 19:24 UTCEPSS rescore
  22. 2026-06-18 17:51 UTCEPSS rescore
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  24. 2026-06-17 17:51 UTCEPSS rescore
  25. 2026-06-16 17:51 UTCEPSS rescore
  26. 2026-06-16 17:51 UTCEPSS rescore
  27. 2026-06-15 17:46 UTCEPSS rescore
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  31. 2026-06-12 23:10 UTCEPSS rescore
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  36. 2026-06-08 14:15 UTCEPSS rescore
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  38. 2026-06-07 15:23 UTCEPSS rescore
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  40. 2026-06-06 13:46 UTCEPSS rescore
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  42. 2026-06-06 13:46 UTCEPSS rescore
  43. 2026-06-05 22:45 UTCEPSS rescore
  44. 2026-06-05 06:09 UTCEPSS rescore
  45. 2026-06-05 06:09 UTCEPSS rescore
  46. 2026-06-04 13:10 UTCEPSS rescore
  47. 2026-06-04 13:10 UTCEPSS rescore
  48. 2026-06-02 20:11 UTCEPSS rescore
  49. 2026-06-02 20:11 UTCEPSS rescore
  50. 2026-06-01 13:50 UTCEPSS rescore
  51. 2026-06-01 13:50 UTCEPSS rescore
  52. 2026-05-31 22:29 UTCEPSS rescore
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  54. 2026-05-31 00:15 UTCEPSS rescore
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  56. 2026-05-29 13:42 UTCEPSS rescore
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  58. 2026-05-28 13:43 UTCEPSS rescore
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  60. 2026-05-27 13:39 UTCEPSS rescore
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  62. 2026-05-27 13:39 UTCEPSS rescore
  63. 2026-05-26 13:42 UTCEPSS rescore
  64. 2026-05-26 08:03 UTCEG score recompute
  65. 2026-05-26 08:03 UTCGHSA enrichment
  66. 2026-05-26 07:17 UTCEPSS rescore
  67. 2026-05-26 07:17 UTCEPSS rescore
  68. 2026-05-26 07:17 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-34741?
CVE-2021-34741 is a high vulnerability published on November 4, 2021. A vulnerability in the email scanning algorithm of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to perform a denial of service (DoS) attack against an affected device. This vulnerability is due to insufficient input validation of…
When was CVE-2021-34741 disclosed?
CVE-2021-34741 was first published in the National Vulnerability Database on November 4, 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-2021-34741 actively exploited?
CVE-2021-34741 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 66.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-34741?
CVE-2021-34741 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2021-34741?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-34741, 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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