Threats / Cisco / CVE-2018-0174
CVE-2018-0174
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Cisco IOS XE Software vulnerability
A vulnerability in DHCP option 82 encapsulation in Cisco IOS XE Software allows denial-of-service attacks through malformed DHCP packets.
Verdict
Today item — known-exploited.
This improper input validation flaw enables network-based DoS attacks against affected Cisco devices. The low EPSS score reflects limited attack complexity, but active exploitation in the wild confirms practical threat.
CISA KEV Yes · 2022-03-035EPSS 0.07758 (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 0.07758 — 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, IOS XE Software. 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-20 Improper Input Validation.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.
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 malformed DHCP packets with invalid option 82 encapsulation to trigger processing errors on the target device.
Business
Network availability is disrupted as the affected router or switch becomes unresponsive to legitimate traffic.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I send a flood of these crafted packets from the network segment to exhaust device resources.
Business
Critical infrastructure dependent on the device experiences service degradation or outage.
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