A vulnerability in the Bidirectional Forwarding Detection (BFD) offload implementation of Cisco Catalyst 4500 Series Switches and Cisco Cat…

published 2018-03-28 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-0978

cvss: 8.6; version 3.1, CNA
cisa kev: Exploited; added 2022-03-03
epss: 7.7%; EPSS 7.7% chance of exploitation in 30 days, percentile 94%
public exploits: 0; none known

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.

Patch / fix

cisa required action Apply updates per vendor instructions.

Timeline

2018-03-28 Published
2022-03-03 Added to CISA KEV
2022-03-17 CISA patch deadline
2024-11-08 CISA SSVC: exploitation active

Known exploited

Added: 4 y ago (2022-03-03)
Patch by: 2022-03-17 (4 y ago)
Ransomware: Not known
Required action: Apply updates per vendor instructions.
Vendor, product: Cisco, Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches
CISA name: Cisco Catalyst Bidirectional Forwarding Detection Denial-of-Service Vulnerability

CISA SSVC

Exploitation: Active, exploited in the wild
Automatable: yes
Technical impact: partial
Assessed: 2 y ago (2024-11-08)

Exploit prediction

7.74% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CNA	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	2.0	7.8	AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

n/a Cisco IOS and IOS XE

Classification

Weakness

CWE-388 7PK - Errors
CWE-755 Improper Handling of Exceptional Conditions

Technology feeds

Cisco IOS rss critical rss

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-bfd
vendor-advisory
securitytracker.com /id/1040587
vdb-entry, third-party-advisory
securityfocus.com /bid/103565
vdb-entry, third-party-advisory
ics-cert.us-cert.gov /advisories/ICSA-18-107-05
third-party-advisory, us-government-resource
cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0155
government-resource, us-government-resource

Sources

CVE List CVE-2018-0155
NVD CVE-2018-0155

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary