CVE-2024-20353

HIGHNVD 8.69.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2024-04-24), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.6 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
8.6
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 71%CVSS: 8.6Exploit: NoneExposed: 0

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

A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to incomplete error checking when parsing an HTTP header. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted web server on a device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.

CVSS v3
8.6
EG Score
9.0(high)
EG Risk
96(Attend)
EG Risk 96/100SSVC: Attend

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
Severity90% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS
99.3%
KEV
⚠ Exploited

Published

April 24, 2024

Last Modified

October 28, 2025

Advisory Details (3)

Auto-updated Jun 2, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-20353
generic

ArcaneDoor - New espionage-focused campaign found targeting perimeter network devices

https://blog.talosintelligence.com/arcanedoor-new-espionage-focused-campaign-found-targeting-perimeter-network-devices/
generic

Cisco Adaptive Security Appliance and Firepower Threat Defense Software Web Services Denial of Service Vulnerability

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-websrvs-dos-X8gNucD2

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 39× in last 7d / 202× 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 413 total refreshes for this CVE.

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

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Frequently asked(6)

What is CVE-2024-20353?
CVE-2024-20353 is a high vulnerability published on April 24, 2024. A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.…
When was CVE-2024-20353 disclosed?
CVE-2024-20353 was first published in the National Vulnerability Database on April 24, 2024, with the most recent update on October 28, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2024-20353 actively exploited?
Yes. CISA added CVE-2024-20353 to the Known Exploited Vulnerabilities catalog on April 24, 2024, affecting Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD). KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2024-20353?
CVE-2024-20353 has a CVSS v3 base score of 8.6 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2024-20353?
CVE-2024-20353 affects Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD). The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2024-20353?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2024-20353, 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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