CVE-2020-3571: Cisco Firepower 4110 ICMP Flood Denial of Service Vulnerability

Severity: high (CVSS 8.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-10-21 · updated 2026-08-11
Weakness: CWE-400

Description

A vulnerability in the ICMP ingress packet processing of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 4110 appliances could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to incomplete input validation upon receiving ICMP packets. An attacker could exploit this vulnerability by sending a high number of crafted ICMP or ICMPv6 packets to an affected device. A successful exploit could allow the attacker to cause a memory exhaustion condition that may result in an unexpected reload. No manual intervention is needed to recover the device after the reload.

Affected products

Cisco Firepower Threat Defense Software: from 6.3.0 before 6.3.0.6; from 6.4.0 before 6.4.0.10; from 6.5.0 before 6.5.0.5 — fixed in 6.3.0.6, 6.4.0.10, 6.5.0.5

How to fix

Upgrade to a fixed version: Cisco Firepower Threat Defense Software 6.3.0.6, 6.4.0.10, 6.5.0.5. Check the vendor advisory for mitigations.

References

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