{"id":"CVE-2018-0172","published":"2018-03-28T22:29:01Z","modified":"2026-06-17T01:29:59Z","title":"Cisco IOS and IOS XE Software Improper Input Validation Vulnerability","vendor":"Cisco","product":"IOS and IOS XE Software","tier":"core","eol":null,"description":{"text":"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 a heap overflow condition on the affected device, which will cause the device to reload and result in a DoS condition. Cisco Bug IDs: CSCvg62730.","provenance":"source","from":"NVD"},"summary":{"text":"A flaw in the DHCP option 82 encapsulation functionality of Cisco IOS and IOS XE Software results from incomplete input validation of option 82 data received in DHCPv4 packets from DHCP relay agents. An unauthenticated remote attacker can exploit it by sending a crafted DHCPv4 packet to an affected device, causing a heap overflow that reloads the device and produces a denial of service, with no authentication or user interaction required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:13:19Z"},"cvss":{"score":8.6,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.0782,"percentile":0.9465,"date":"2026-10-28","provenance":"source"},"kev":{"dateAdded":"2022-03-03","dueDate":"2022-03-17","ransomware":false,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2018-0172","provenance":"source"},"vulncheckKev":{"dateAdded":"2022-03-03","exploitedFirstSeen":"2022-03-03","ransomware":false,"evidence":[{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2022-03-03"},{"url":"https://www.cisco.com/c/en/us/support/docs/csa/cisco-sa-20180328-dhcpr1.html","date":"2022-12-15"}],"evidenceTotal":2,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-787","name":"Out-of-bounds Write"},{"id":"CWE-20","name":"Improper Input Validation"}],"references":[{"url":"http://www.securityfocus.com/bid/103552","tags":["Third Party Advisory","VDB Entry"]},{"url":"http://www.securitytracker.com/id/1040591","tags":["Third Party Advisory","VDB Entry"]},{"url":"https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04","tags":["Third Party Advisory","US Government Resource"]},{"url":"https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05","tags":["Third Party Advisory","US Government Resource"]},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr1","tags":["Vendor Advisory"]},{"url":"https://www.tenable.com/security/research/tra-2018-06","tags":["Third Party Advisory"]},{"url":"http://www.securityfocus.com/bid/103552","tags":["Third Party Advisory","VDB Entry"]},{"url":"http://www.securitytracker.com/id/1040591","tags":["Third Party Advisory","VDB Entry"]},{"url":"https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04","tags":["Third Party Advisory","US Government Resource"]},{"url":"https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05","tags":["Third Party Advisory","US Government Resource"]},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr1","tags":["Vendor Advisory"]},{"url":"https://www.tenable.com/security/research/tra-2018-06","tags":["Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0172","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Remote unauthenticated network packet exploits public-facing service","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device","start":444,"end":545}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1499.004","name":"Application or System Exploitation","tactics":["impact"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Crash causes application-layer denial of service","mappingType":"primary_impact","evidence":[{"from":"description","quote":"will cause the device to reload and result in a DoS condition","start":658,"end":719}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2018-0995","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2018-0995","exploited":true,"exploitedSince":"2022-03-03","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1499.004"],"provenance":"ai"}],"timeline":[{"date":"2018-03-28","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2018-0172","provenance":"source"},{"date":"2022-03-03","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","provenance":"source"},{"date":"2022-03-03","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2022-03-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2018-0995","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":1436},"priority":{"score":63.0,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 1701 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":18.93,"detail":"percentile 0.9465"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":6.02,"detail":"base score 8.6"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]},"lineage":{"familyId":"fam-class-cisco-ios-and-ios-xe-cwe-20"}}