How severe is CVE-2018-0155?

CVE-2018-0155 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-0155 being actively exploited?

Yes. CVE-2018-0155 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2018-0155?

CVE-2018-0155 primarily affects Cisco Ios. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-0155?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2018-0155 have an EU (EUVD) identifier?

Yes. CVE-2018-0155 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2018-0978. It is also flagged as exploited in the EUVD (since 2022-03-03).

When was CVE-2018-0155 published?

CVE-2018-0155 was published on 2018-03-28 and last updated on 2026-06-17.

CVE-2018-0155

CVE-2018-0155 is a high-severity vulnerability in Cisco Ios with a CVSS 3.x base score of 8.6. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-03-03). The underlying weakness is classified as CWE-755.

Key facts

Severity: High (CVSS 3.x base score 8.6)
CVSS v2: 7.8
EPSS exploit prediction: 8% (94th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-03-03)
EU (EUVD) id: EUVD-2018-0978
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-03-03)
Weakness: CWE-755
Affected product: Cisco Ios
Published: 2018-03-28
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-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. 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.
How severe is CVE-2018-0155?: CVE-2018-0155 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-0155 being actively exploited?: Yes. CVE-2018-0155 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2018-0155?: CVE-2018-0155 primarily affects Cisco Ios. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-0155?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2018-0155 have an EU (EUVD) identifier?: Yes. CVE-2018-0155 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2018-0978. It is also flagged as exploited in the EUVD (since 2022-03-03).
When was CVE-2018-0155 published?: CVE-2018-0155 was published on 2018-03-28 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:cisco:ios:3.6\(2\)e:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:3.6\(2\)e:*:*:*:*:*:*:*

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