CVEs / CVE-2018-0155

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

Known exploited in the CISA KEV catalog since 3 Mar 2022
high 8.6 CVSS 3.1 (NVD)
EPSS 7.74% chance of exploitation in the next 30 days, higher than 94% of CVEs (30 Oct 2026)
Last changed at its sources 17 Jun 2026

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Summary

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.
CISA, Known Exploited Vulnerabilities catalog

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.
The CVE record, via NVD · published 28 Mar 2018 · NVD status: Analyzed

Affected and fixed versions

As stated by the CVE record (from the CNA)
Product	Affected	Fixed in
n/a Cisco IOS and IOS XE	Cisco IOS and IOS XE	—

Exploitation

In CISA KEV since	3 Mar 2022
Due date for US federal agencies	17 Mar 2022
Used in ransomware campaigns	Unknown
Required action	Apply updates per vendor instructions.

Severity

CVSS 3.1	8.6 high `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H` Scored by NVD
Weakness	CWE-388, CWE-755

References

CVE-2018-0155 on NVD
CVE-2018-0155 in the CISA KEV catalog
http://www.securityfocus.com/bid/103565 Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1040587 Third Party Advisory, VDB Entry
https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05 Third Party Advisory, US Government Resource
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-bfd Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0155 US Government Resource

Sources

Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.

This product uses data from the NVD API but is not endorsed or certified by the NVD.