{"id":"CVE-2018-0173","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-0173","generatedAt":"2026-10-28T21:31:40.664Z","title":"Cisco IOS and IOS XE Software Improper Input Validation Vulnerability","description":"A vulnerability in the Cisco IOS Software and Cisco IOS XE Software function that restores encapsulated option 82 information in DHCP Version 4 (DHCPv4) packets could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a Relay Reply denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of encapsulated option 82 information that it receives in DHCPOFFER messages from DHCPv4 servers. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device, which the device would then forward to a DHCPv4 server. When the affected software processes the option 82 information that is encapsulated in the response from the server, an error could occur. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvg62754.","published":"2018-03-28T22:29:01.000Z","lastModified":"2026-06-17T01:30:00.000Z","status":"Analyzed","sourceIdentifier":"psirt@cisco.com","cvss":{"version":"3.1","score":8.6,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H"},"cwe":["CWE-20"],"affected":["cisco/ios","cisco/ios xe"],"epss":{"score":0.07608,"percentile":0.94521,"date":"2026-10-27","history":[]},"kev":{"listed":true,"dateAdded":"2022-03-03","dueDate":"2022-03-17","knownRansomwareCampaignUse":"Unknown","notes":"Apply updates per vendor instructions.\nhttps://nvd.nist.gov/vuln/detail/CVE-2018-0173"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 March 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"http://www.securityfocus.com/bid/103545","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"psirt@cisco.com"},{"url":"http://www.securitytracker.com/id/1040591","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"psirt@cisco.com"},{"url":"https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04","tags":["Third Party Advisory","US Government Resource"],"source":"psirt@cisco.com"},{"url":"https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05","tags":["Third Party Advisory","US Government Resource"],"source":"psirt@cisco.com"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr2","tags":["Vendor Advisory"],"source":"psirt@cisco.com"},{"url":"https://www.tenable.com/security/research/tra-2018-06","tags":["Third Party Advisory"],"source":"psirt@cisco.com"},{"url":"http://www.securityfocus.com/bid/103545","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1040591","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04","tags":["Third Party Advisory","US Government Resource"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05","tags":["Third Party Advisory","US Government Resource"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr2","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.tenable.com/security/research/tra-2018-06","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0173","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-0173","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}