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Vulnerabilities

Vulnerability · CVE-2018-0155

Cisco Catalyst Bidirectional Forwarding Detection Denial-of-Service Vulnerability

Published Mar 28, 2018 · catalog updated Jun 16, 2026 · Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches

Patch now

CVE-2018-0155 is in the CISA known-exploited catalog, due Mar 17, 2022. Confirm Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
High8.6
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
7.74%
Remediation
Remediation guidance
Affected products
cpe cisco/ios · cpe cisco/ios xe · vendor Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe cisco/ios3.6\(2\)e
  • cpe cisco/ios xe3.6\(2\)e
  • vendor Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switchesversion unspecified

How to fix CVE-2018-0155

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2018-0155 is in the CISA known-exploited catalog, due Mar 17, 2022. Confirm Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with cisco/ios xe 3.6\(2\)e. Apply updates per vendor instructions.

What should an analyst verify?

CWE-388; CWE-755: Improper Handling of Exceptional Conditions. EPSS 7.74%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Cisco security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 28, 2018 · Catalog

    Detected

    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 incomp

  2. Mar 3, 2022 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Mar 17, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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 incomp

Sources

  • CISA KEVConfirmed exploitationCVE-2018-0155

    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.gov
  • CVE.orgVulnerability recordCVE-2018-0155

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2018-0155

    30-day exploitation probability 7.7%

    first.org
  • NIST NVDVulnerability recordCVE-2018-0155

    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 servic

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2018-0155

    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-servic

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.