CVE-2022-20746: Cisco Firepower Threat Defense Software TCP Proxy Denial of Service Vulnerability

Severity: high (CVSS 7.5 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: 2022-05-03 · updated 2026-08-11
Weakness: CWE-476

Description

A vulnerability in the TCP proxy functionality of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper handling of TCP flows. An attacker could exploit this vulnerability by sending a crafted stream of TCP traffic through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Affected products

Cisco Firepower Threat Defense Software: before 6.4.0.15; from 6.5.0 before 6.6.5.2; from 7.0.0 before 7.0.2; 7.1.0 — fixed in 6.4.0.15, 6.6.5.2, 7.0.2

How to fix

Upgrade to a fixed version: Cisco Firepower Threat Defense Software 6.4.0.15, 6.6.5.2, 7.0.2. Check the vendor advisory for mitigations.

References

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