Vulnerabilities
CVE-2018-0174 — Cisco IOS Software and Cisco IOS XE Software Improper Input Validation Vulnerability
CVE-2018-0174 · Cisco IOS and IOS XE · CVSS 8.6 · KEV
In brief
- Severity · CVSS
- High8.6CVSS 3.1, High
- EPSS
- 8%
- CISA KEV
- Known exploited, listed since 3 Mar 2022
- CERT-FR
- No advisory or alert referenced in the catalog
- Vendor
- Cisco
- Published · Modified
- ·
- Last verified
Summary
A vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of option 82 information that it receives in DHCP Version 4 (DHCPv4) packets from DHCP relay agents. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuh91645.
Weakness: CWE-20
Title, description and the vendor's statements are quoted from the CVE record; a vendor's advisory is summarised in Patcharo's words, with a link.
Affected and fixed versions
Per product and release branch, as the vendor's CVE record and official advisory state them. A fixed release is shown only when a document names it: the vendor's, or CERT-FR's for Check Point, with its source.
Cisco IOS and IOS XE
- —Affected versionsCisco IOS and IOS XEFirst fixed releaseNot published in the sources followed
The vendor states fixes are available; the releases per branch are in its advisory.
Remediation
Fix available
Vendor fix
Cisco has released updates that fix this vulnerability; its advisory lists them.
SourceCisco Security Advisory cisco-sa-20180328-dhcpr3· revised 15 Dec 2022
Workarounds (vendor)
Cisco states in its advisory that no workaround is available.
Last verified 1 Oct 2026 at 09:30 UTC
Known exploitation
Added to CISA KEV on 3 Mar 2022
Federal remediation due date: 17 Mar 2022
8% probability of exploitation in the next 30 days (percentile 94%).
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CERT-FR
No CERT-FR advisory or alert of the last two years references this CVE, for the vendors Patcharo covers.
Timeline
- Published by the source
- Added to CISA KEV
- CISA remediation due date
- Source record last modified
- EPSS score computed
- Last verified by Patcharo
Official sources
- Cisco (CVE record)retrieved 1 Oct 2026 at 09:30 UTC
- CISA Known Exploited Vulnerabilitiesretrieved 1 Oct 2026 at 09:28 UTC
- NVDretrieved 27 Sept 2026 at 23:44 UTC
- FIRST EPSSretrieved 30 Sept 2026 at 00:17 UTC
- Cisco Security Advisory cisco-sa-20180328-dhcpr3retrieved 1 Oct 2026 at 09:30 UTC
References
Vendor advisory
Cisco · CISA Known Exploited Vulnerabilities · NVD · FIRST EPSS · Cisco Security Advisory cisco-sa-20180328-dhcpr3
How Patcharo reads this
Affected and fixed releases come from the vendor's structured statements and are matched against exact versions; CVSS from NVD, exploitation from CISA KEV and the vendor's own advisory, probability from FIRST EPSS. Missing data stays Unknown and never becomes Not affected.
Read the methodologyRead the guide: Cisco Secure Firewall release trains: Threat Defense, Management Center and ASA versions explained