Threats / Cisco / CVE-2018-0155
CVE-2018-0155
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Cisco Catalyst 4500 Series Switches and 4500-X vulnerability
A vulnerability in BFD offload implementation on Cisco Catalyst 4500 Series Switches allows unauthenticated remote attackers to crash the iosd process, causing denial of service.
Verdict
Today item — known-exploited.
Unauthenticated remote attackers can exploit improper input validation in BFD processing to trigger a process crash on affected Catalyst switches, disrupting network operations without requiring credentials or authentication.
CISA KEV Yes · 2022-03-035EPSS 0.07894 (verify live)6CVSS 8.6 (CISA)4CISA SSVC Exploitation: active · Automatable: yes · Impact: partial4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-03).
Probability (EPSS)
EPSS 0.07894 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 8.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H) · Affected: Cisco, Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-388 CWE-388.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: partialCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 1436 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
WeaknessCWE-388 · CWE-388
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft and send malformed BFD packets to the target switch from the network.
Business
Network availability is disrupted as the iosd process crashes, causing the switch to become unresponsive.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I repeat the attack to maintain the denial-of-service condition across the affected infrastructure.
Business
Sustained outages impact business continuity, customer connectivity, and operational efficiency of network services.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05