CVE-2018-0155: Cisco Catalyst Bidirectional Forwarding Detection Denial-of-Service Vulnerability

Severity: high (CVSS 8.6 v3.1)
Exploited in the wild: yes — in CISA KEV since 2022-03-03
EPSS: 7.7% 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-388

Description

A vulnerability in the Bidirectional Forwarding Detection (BFD) offload implementation of Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches could allow an unauthenticated, remote attacker to cause a crash of the iosd process, causing a denial of service (DoS) condition. The vulnerability is due to insufficient error handling when the BFD header in a BFD packet is incomplete. An attacker could exploit this vulnerability by sending a crafted BFD message to or across an affected switch. A successful exploit could allow the attacker to trigger a reload of the system. This vulnerability affects Catalyst 4500 Supervisor Engine 6-E (K5), Catalyst 4500 Supervisor Engine 6L-E (K10), Catalyst 4500 Supervisor Engine 7-E (K10), Catalyst 4500 Supervisor Engine 7L-E (K10), Catalyst 4500E Supervisor Engine 8-E (K10), Catalyst 4500E Supervisor Engine 8L-E (K10), Catalyst 4500E Supervisor Engine 9-E (K10), Catalyst 4500-X Series Switches (K10), Catalyst 4900M Switch (K5), Catalyst 4948E Ethernet Switch (K5). Cisco Bug IDs: CSCvc40729.

Affected products

Cisco IOS: 3.6(2)e
Cisco IOS XE: 3.6(2)e

References

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