CVE-2018-0167Cisco IOS, XR, and XE Software Buffer Overflow Vulnerability

Patch nowHigh8.8ExploitedEPSS 3.4%

CVE-2018-0167 is a memory buffer error in Cisco IOS, XR, and XE Software, rated high (8.8 on CVSS 3.1).

Why this priority: Exploited in the wild: listed in CISA's KEV catalog.

Published 28 Mar 2018 · Updated 17 Jun 2026 · NVD status: Analyzed

What it is

Code reads or writes outside the memory it was given, which can corrupt the process.

How it is reached

An attacker can exploit it from the same local network segment, without an account, and nobody has to click anything.

What an attacker gains

A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker crash the process, read memory, or in the worst case run code.

Is it being exploited?

CISA added it to the Known Exploited Vulnerabilities catalog on 2022-03-03: it is being exploited in the wild. EPSS estimates a 3.4% chance of exploitation activity in the next 30 days, higher than 89% of scored CVEs.

What to do

Treat it as urgent: it is on CISA's KEV list. CISA's deadline for US federal agencies: 2022-03-17.
Upgrade Cisco IOS, XR, and XE Software to 5.1.3 or later.
Segment the networks that can reach it.
Check exposed instances for signs of compromise, not only for the version.

Description from NVD

Multiple Buffer Overflow vulnerabilities in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges on an affected device. Cisco Bug IDs: CSCuo17183, CSCvd73487.

What this means for your architecture.

A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.

Components it touches

Network edge devices: VPNs, firewalls, routers and gateways. They sit between the internet and internal networks, so a flaw in one is often the first step into everything behind it.
Operating systems on servers, workstations or devices. Everything on the host inherits the flaw.
Native code: operating systems, browsers and firmware. The flaw sits wherever native code reads untrusted data.
Network appliances and media or file parsers. The flaw sits wherever native code reads untrusted data.

Trust boundaries in play

Local network segment. The attacker must share a network segment with the target.
Wherever native code reads untrusted data. An attacker who crosses it can crash the process, read memory, or in the worst case run code.

Questions to answer about your own systems

Where does Cisco IOS, XR, and XE Software run in your systems, and at which version?
Which network segments can reach them?
What can it reach once compromised: which data stores, secrets and services?

See how Veriom maps an architecture Take the interactive tour

Advisories

Sources

CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.