High 8.6Known exploited (CISA KEV)Published Mar 28, 2018

CVE-2018-0155A 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,…

Updated under an hour ago (2026-10-19 08:40 UTC)

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It affects cisco ios and 1 other product. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Mar 3, 2022; federal agencies had to remediate by Mar 17, 2022. Treat that date as your deadline.

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Exploited in the last 30 days

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.

CVSS: 8.6 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness (CWE): CWE-388
Known exploited: Added to CISA KEV Mar 3, 2022; federal remediation due Mar 17, 2022Apply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 7.74% (percentile 95)
Assigned by: cisco
NVD analysis: Analyzed
Record last updated: Jan 12, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

cisco ios cisco:ios	3.6(2)e; 3.6(2)e	NVD
cisco ios_xe cisco:ios_xe	3.6(2)e; 3.6(2)e	NVD

References

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.