Cisco Catalyst Bidirectional Forwarding Detection Denial-of-Service Vulnerability

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.

Weakness: CWE-388, CWE-755

Patcharo shows this vulnerability for information but does not match versions for this product yet.

• n/a Cisco IOS and IOS XE · Cisco IOS and IOS XE

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-bfd(opens in a new tab)
• https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05(opens in a new tab)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0155(opens in a new tab)

Cisco (CVE record)

Cisco (CVE record) · 27 Sept 2026, 23:46 UTC · Parser patcharo-cve5/1.1.0

CISA Known Exploited Vulnerabilities

CISA Known Exploited Vulnerabilities · 27 Sept 2026, 23:42 UTC · Parser patcharo-kev/1.0.0

NVD

NVD · 27 Sept 2026, 23:44 UTC · Parser patcharo-nvd/1.0.0

FIRST EPSS

FIRST EPSS · 27 Sept 2026, 23:46 UTC · Parser patcharo-epss/1.0.0

Last verified: 28 Sept 2026, 02:31 UTC