{"id":"CVE-2017-12240","url":"https://www.cyber-defence.io/tools/cve/CVE-2017-12240","generatedAt":"2026-10-29T00:34:56.674Z","title":"Cisco IOS and IOS XE Software DHCP Remote Code Execution Vulnerability","description":"The DHCP relay subsystem of Cisco IOS 12.2 through 15.6 and Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system. The attacker could also cause an affected system to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to a buffer overflow condition in the DHCP relay subsystem of the affected software. An attacker could exploit this vulnerability by sending a crafted DHCP Version 4 (DHCPv4) packet to an affected system. A successful exploit could allow the attacker to execute arbitrary code and gain full control of the affected system or cause the affected system to reload, resulting in a DoS condition. Cisco Bug IDs: CSCsm45390, CSCuw77959.","published":"2017-09-29T01:34:49.000Z","lastModified":"2026-06-17T01:02:57.000Z","status":"Analyzed","sourceIdentifier":"psirt@cisco.com","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-20","CWE-119"],"affected":["cisco/ios"],"epss":{"score":0.13773,"percentile":0.96495,"date":"2026-10-27","history":[]},"kev":{"listed":true,"dateAdded":"2022-03-03","dueDate":"2022-03-24","knownRansomwareCampaignUse":"Unknown","notes":"Apply updates per vendor instructions.\nhttps://nvd.nist.gov/vuln/detail/CVE-2017-12240"},"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 24 March 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"http://www.securityfocus.com/bid/101034","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"psirt@cisco.com"},{"url":"http://www.securitytracker.com/id/1039445","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"psirt@cisco.com"},{"url":"https://quickview.cloudapps.cisco.com/quickview/bug/CSCsm45390","tags":["Vendor Advisory"],"source":"psirt@cisco.com"},{"url":"https://quickview.cloudapps.cisco.com/quickview/bug/CSCuw77959","tags":["Vendor Advisory"],"source":"psirt@cisco.com"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-dhcp","tags":["Vendor Advisory"],"source":"psirt@cisco.com"},{"url":"http://www.securityfocus.com/bid/101034","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1039445","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://quickview.cloudapps.cisco.com/quickview/bug/CSCsm45390","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://quickview.cloudapps.cisco.com/quickview/bug/CSCuw77959","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-dhcp","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12240","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2017-12240","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."}