CVE-2019-1694: Cisco Adaptive Security Appliance Software

High severity, CVSS 8.6. EPSS: 2.5% chance of exploitation in the next 30 days.

A vulnerability in the TCP processing engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to the improper handling of TCP traffic. An attacker could exploit this vulnerability by sending a specific sequence of packets at a high rate through an affected device. A successful exploit could allow the attacker to temporarily disrupt traffic through the device while it reboots.

Affected products

• Cisco Adaptive Security Appliance Software: before 9.4.4.34 (fixed in 9.4.4.34); from 9.5, before 9.6.4.25 (fixed in 9.6.4.25); from 9.7, before 9.8.4 (fixed in 9.8.4); from 9.9, before 9.9.2.50 (fixed in 9.9.2.50); from 9.10, before 9.10.1.17 (fixed in 9.10.1.17)
• Cisco Secure Firewall Threat Defense: before 6.2.3.12 (fixed in 6.2.3.12); from 6.3.0, before 6.3.0.3 (fixed in 6.3.0.3)

Published 2019-05-03. Last modified 2026-08-11.