CVE-2018-0189

Severity: medium (CVSS 5.3 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-03-28 · updated 2026-06-17
Weakness: CWE-399

Description

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; before 15.5\(3\)m5; before 15.4\(3\)s7; before 15.4\(2\)s1; before 15.4\(1\)s1; before 15.4\(1\)s0a — fixed in 15.2\(1\)e1, 15.2\(2\)e1, 15.2\(4\)e5, 15.2\(5\)e1, 15.4\(1\)s0a, 15.4\(1\)s1

How to fix

Upgrade to a fixed version: Cisco IOS XE 15.2\(1\)e1, 15.2\(2\)e1, 15.2\(4\)e5, 15.2\(5\)e1. Check the vendor advisory for mitigations.

References

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