CVE-2019-1751: Cisco IOS

High severity, CVSS 7.5. EPSS: 2.5% chance of exploitation in the next 30 days.

A vulnerability in the Network Address Translation 64 (NAT64) functions of Cisco IOS Software could allow an unauthenticated, remote attacker to cause either an interface queue wedge or a device reload. The vulnerability is due to the incorrect handling of certain IPv4 packet streams that are sent through the device. An attacker could exploit this vulnerability by sending specific IPv4 packet streams through the device. An exploit could allow the attacker to either cause an interface queue wedge or a device reload, resulting in a denial of service (DoS) condition.

Affected products

• Cisco IOS: version 15.4(1)cg1 only; version 15.4(1)t only; version 15.4(1)t1 only; version 15.4(1)t2 only; version 15.4(1)t3 only; version 15.4(1)t4 only; …

Published 2019-03-28. Last modified 2026-06-17.