Exploited CVEs / Cisco / CVE-2018-0173
CVE-2018-0173
Cisco IOS and IOS XE Software Improper Input Validation Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2022-03-17 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Cisco Security Advisories (PSIRT), linked below.
Actively exploited Cisco IOS and IOS XE Software vulnerability, High severity, CVSS 8.6. Added to the CISA KEV catalog 2022-03-03.
Risk summary
Updated July 27, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2018-0173
This flaw is in a narrow spot: the routine that restores encapsulated DHCP option 82 information in DHCPv4 packets on Cisco IOS and IOS XE, and a crafted packet can crash the device for a denial-of-service. Anything acting as a DHCP relay or serving DHCPv4 with option 82 handling is exposed, which covers many access and distribution switches and routers. It carries a High severity rating (CVSS 8.6) and sits on the CISA KEV list as confirmed exploited, so this is a proven outage vector rather than a theoretical one.
Do this: Identify which IOS and IOS XE devices process DHCPv4 option 82 traffic and schedule the Cisco fixed-release upgrade for those first.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2018-0173
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2018-0173
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2022-03-17 (past due).
Apply updates per vendor instructions.
Official fix for CVE-2018-0173
The authoritative fix and affected-version list are published by the vendor. Find the IOS and IOS XE Software advisory on Cisco Security Advisories (PSIRT).
Common questions about CVE-2018-0173
Is CVE-2018-0173 actively exploited?
Yes. CVE-2018-0173 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2022-03-03, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 7.8%.
What is the CISA deadline and required action for CVE-2018-0173?
CISA set the federal (BOD 22-01) remediation due date at 2022-03-17, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.
What fixes CVE-2018-0173?
The authoritative fix is in the vendor advisory: see Cisco Security Advisories (PSIRT) for the patched IOS and IOS XE Software versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2018-0173?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2018-0173's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
More exploited Cisco CVEs
The newest Cisco entries on the CISA KEV catalog:
All Cisco exploited CVEs on one page: Cisco vulnerabilities actively exploited.
Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.
