CVE-2018-0155
HighExploitedPublic exploitA 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…
Published Mar 28, 2018 · Updated Jan 13, 2026
Key Facts
Patch immediately- CVE-2018-0155 is a high-severity vulnerability (CVSS 8.6 v3.1) affecting IOS (Cisco), IOS Xe (Cisco), Cisco IOS and IOS XE.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 3, 2022. Public exploit code is available.
- EPSS estimates a 7.7% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
8.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS (30-day exploit likelihood)
7.7%
Higher than 94.5% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2018-0155 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Mar 3, 2022 | Mar 17, 2022 | Not reported |
| Industry KEV feed | Mar 3, 2022 | Mar 17, 2022 | Not reported |
| CIRCL KEV | Mar 3, 2022 | Mar 17, 2022 | Not reported |
| ENISA EUVD | Mar 3, 2022 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| IOSCisco | 3.6\(2\)e | n/a |
| IOS XeCisco | 3.6\(2\)e | n/a |
| Cisco IOS and IOS XE | >= Cisco IOS and IOS XE | n/a |
Timeline
Publicly disclosed
Mar 28, 2018
Added to CISA KEV
Mar 3, 2022
Added to Industry KEV feed
Mar 3, 2022
Added to CIRCL KEV
Mar 3, 2022
Added to ENISA EUVD
Mar 3, 2022
Last updated
Jan 13, 2026
Weakness Type
- CWE-388
- CWE-755 Improper Handling of Exceptional Conditions
References
- advisoryhttps://ics-cert.us-cert.gov/advisories/ICSA-18-107-05
- advisoryhttps://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-bfd
- advisory103565
- advisory1040587
- exploitVulnCheck exploitation report
FAQ
Common Questions.
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.
Affected: IOS (Cisco) versions 3.6\(2\)e; IOS Xe (Cisco) versions 3.6\(2\)e; Cisco IOS and IOS XE versions >= Cisco IOS and IOS XE. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 3, 2022.
Yes. It was added on Mar 3, 2022 with a federal remediation due date of Mar 17, 2022.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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