{"cve":"CVE-2020-3509","nvd":{"published":"2020-09-24T18:15:21.073","modified":"2026-06-17T03:18:28.093","status":"Modified","description":"A vulnerability in the DHCP message handler of Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, remote attacker to cause the supervisor to crash, which could result in a denial of service (DoS) condition. The vulnerability is due to insufficient error handling when DHCP version 4 (DHCPv4) messages are parsed. An attacker could exploit this vulnerability by sending a malicious DHCPv4 message to or through a WAN interface of an affected device. A successful exploit could allow the attacker to cause a reload of the affected device. Note: On Cisco cBR-8 Converged Broadband Routers, all of the following are considered WAN interfaces: 10 Gbps Ethernet interfaces 100 Gbps Ethernet interfaces Port channel interfaces that include multiple 10 and/or 100 Gbps Ethernet interfaces","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","score":8.6},"cwes":["CWE-203","CWE-388"],"references":["https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-dhcp-dos-JSCKX43h","https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-dhcp-dos-JSCKX43h"],"products":["cisco:ios_xe"],"source":"nvd","synced_at":"2026-10-19T21:09:53.489947993+00:00"},"epss":{"cve":"CVE-2020-3509","score":0.01415,"percentile":0.72754,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}