CVE-2020-3191 json
Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software IPv6 DNS Denial of Service Vulnerability
published 2020-05-06 6 y ago modified 2026-08-11 2 mo ago also EUVD-2020-24462
- cvss
- 8.6
- version 3.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.9%
- EPSS 1.9% chance of exploitation in 30 days, percentile 79%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- cisco secure_firewall_threat_defense 6.2.3.16, 6.3.0.6, 6.4.0.6
- cisco adaptive_security_appliance_software 9.6.4.36, 9.8.4.12, 9.9.2.66, 9.10.1.37, 9.12.2.9
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 23 mo ago
Exploit prediction
1.86% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.0 | 8.6 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVD | 3.1 | 8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
Affected products
- Cisco Cisco Adaptive Security Appliance (ASA) Software
Classification
- Weakness
-
- CWE-20 Improper Input Validation
References
Sources
- CVE List CVE-2020-3191
- NVD CVE-2020-3191
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