CVE-2020-3191

HIGHNVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

Score 8.6 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 8.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.6EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.9%CVSS: 8.6Exploit: None knownExposed services: Not assessed

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

A vulnerability in DNS over IPv6 packet processing for Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to unexpectedly reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper length validation of a field in an IPv6 DNS packet. An attacker could exploit this vulnerability by sending a crafted DNS query over IPv6, which traverses the affected device. An exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. This vulnerability is specific to DNS over IPv6 traffic only.

CVSS v3
8.6
EG Score
8.6HIGHmedium confidence
EG Risk
54
EG Risk 54/100CISA SSVC

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
Severity86% × 45%
Exploitation2% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
1.9%
EPSS %ILE
78th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

May 6, 2020

Last Modified

August 11, 2026

Advisory Details (1)

Auto-updated Aug 11, 2026
No patch confirmed yet.
generic

Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software IPv6 DNS Denial of Service Vulnerability

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ipv6-67pA658k

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 23× 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 152 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2020-3191?
CVE-2020-3191 is a high vulnerability published on May 6, 2020. A vulnerability in DNS over IPv6 packet processing for Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to unexpectedly reload, resulting in a denial of service (DoS) condition. The…
When was CVE-2020-3191 disclosed?
CVE-2020-3191 was first published on May 6, 2020, with the most recent update on August 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-3191 actively exploited?
CVE-2020-3191 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.9% probability of exploitation in the next 30 days (78th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2020-3191?
CVE-2020-3191 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2020-3191?
No fix for CVE-2020-3191 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix.

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