CVE-2018-0189: Cisco IOS XE

Medium severity, CVSS 5.3. EPSS: 1% chance of exploitation in the next 30 days.

A vulnerability in the Forwarding Information Base (FIB) code of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, network attacker to cause a denial of service (DoS) condition. The vulnerability is due to a limitation in the way the FIB is internally representing recursive routes. An attacker could exploit this vulnerability by injecting routes into the routing protocol that have a specific recursive pattern. The attacker must be in a position on the network that provides the ability to inject a number of recursive routes with a specific pattern. An exploit could allow the attacker to cause an affected device to reload, creating a DoS condition. Cisco Bug IDs: CSCva91655.

Affected products

• Cisco IOS XE: before 15.5\(3\)s5 (fixed in 15.5\(3\)s5); before 15.5\(3\)m5 (fixed in 15.5\(3\)m5); before 15.4\(3\)s7 (fixed in 15.4\(3\)s7); before 15.4\(2\)s1 (fixed in 15.4\(2\)s1); before 15.4\(1\)s1 (fixed in 15.4\(1\)s1); before 15.4\(1\)s0a (fixed in 15.4\(1\)s0a); …

Published 2018-03-28. Last modified 2026-06-17.