CVE•Published 2020-05-06•Modified 2026-08-11•1 article on news•5 live references•NVD data

CVE-2020-3191Cisco · Secure_firewall_threat_defense

Vulnerability data via NVD (ingested)

CVSS v3.1

8.6

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS percentile

Exploit Prediction Scoring System · top 23% of all CVEs

Weaknesses (CWE)

CWE-20Improper Input Validation

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.

Timeline

Published 2020-05-06

Modified 2026-08-11

External references

NVD MITRE Exploit-DB GitHub PoC VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2020-3191

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Cisco Secure Firewall Threat Defense"

All exposed Cisco Secure Firewall Threat Defense instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Secure Firewall Threat Defense"

HTTP body or banner mentions "Secure Firewall Threat Defense" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2020-3191