{"cve":"CVE-2020-3191","nvd":{"published":"2020-05-06T17:15:12.290","modified":"2026-08-11T19:33:44.513","status":"Modified","description":"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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","score":8.6},"cwes":["CWE-20"],"references":["https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ipv6-67pA658k","https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ipv6-67pA658k"],"products":["cisco:adaptive_security_appliance_software","cisco:asa_5505_firmware","cisco:asa_5510_firmware","cisco:asa_5512-x_firmware","cisco:asa_5515-x_firmware","cisco:asa_5520_firmware","cisco:asa_5525-x_firmware","cisco:asa_5540_firmware","cisco:asa_5545-x_firmware","cisco:asa_5550_firmware","cisco:asa_5555-x_firmware","cisco:asa_5580_firmware","cisco:asa_5585-x_firmware","cisco:secure_firewall_threat_defense"],"source":"nvd","synced_at":"2026-10-19T21:04:18.695612450+00:00"},"epss":{"cve":"CVE-2020-3191","score":0.01857,"percentile":0.79207,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}