{"id":"CVE-2021-1451","title":"Cisco IOS XE Software Easy Virtual Switching System Arbitrary Code Execution","summary":"A vulnerability in the Easy Virtual Switching System (VSS) feature of Cisco IOS XE Software for Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches could allow an unauthenticated, remote attacker to execute arbitr…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"vendor","vendor":"Cisco","product":"Cisco IOS XE Software","affected":["ios_xe_software 3.6.0E","ios_xe_software 3.6.1E","ios_xe_software 3.7.0E","ios_xe_software 3.6.0bE","ios_xe_software 3.7.1E","ios_xe_software 3.7.2E","ios_xe_software 3.6.2E","ios_xe_software 3.6.3E","ios_xe_software 3.6.4E","ios_xe_software 3.7.3E","ios_xe_software 3.8.0E","ios_xe_software 3.8.1E","ios_xe_software 3.6.5E","ios_xe_software 3.7.4E","ios_xe_software 3.9.0E","ios_xe_software 3.8.2E","ios_xe_software 3.7.5E","ios_xe_software 3.6.6E","ios_xe_software 3.8.3E","ios_xe_software 3.6.5aE","ios_xe_software 3.6.5bE","ios_xe_software 3.9.1E","ios_xe_software 3.8.4E","ios_xe_software 3.6.7E","ios_xe_software 3.9.2E","ios_xe_software 3.8.5E","ios_xe_software 3.10.0E","ios_xe_software 3.9.2bE","ios_xe_software 3.10.1E","ios_xe_software 3.6.8E","ios_xe_software 3.8.5aE","ios_xe_software 3.10.0cE","ios_xe_software 3.8.6E","ios_xe_software 3.10.2E","ios_xe_software 3.6.9E","ios_xe_software 3.10.1aE","ios_xe_software 3.8.7E","ios_xe_software 3.10.1sE","ios_xe_software 3.11.0E","ios_xe_software 3.6.10E"],"published":"2021-03-24","updated":"2021-03-24","sourceUpdated":"2021-03-24T16:00:00+00:00","source":"CSAF","sourceUrl":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-xe-evss-code-exe-8cw5VSvw","references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-xe-evss-code-exe-8cw5VSvw"},{"url":"https://software.cisco.com"}],"tags":["csaf","vendor-advisory","cisco"],"epss":0.03322,"epssPercentile":0.88385,"ingestedAt":"2026-10-15T11:50:11.867Z","slug":"CVE-2021-1451","body":"## Overview\n\nA vulnerability in the Easy Virtual Switching System (VSS) feature of Cisco IOS XE Software for Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches could allow an unauthenticated, remote attacker to execute arbitrary code on the underlying Linux operating system of an affected device.\r\n\r\nThe vulnerability is due to incorrect boundary checks of certain values in Easy VSS protocol packets that are destined for an affected device. An attacker could exploit this vulnerability by sending crafted Easy VSS protocol packets to UDP port 5500 while the affected device is in a specific state. When the crafted packet is processed, a buffer overflow condition may occur. A successful exploit could allow the attacker to trigger a denial of service (DoS) condition or execute arbitrary code with root privileges on the underlying Linux operating system of the affected device.\r\n\r\nCisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.\r\n\r\n\r\n\r\nThis advisory is part of the March 2021 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2021 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74408\"].\n\n## Vendor advisories\n\n- **cisco-sa-ios-xe-evss-code-exe-8cw5VSvw** · Cisco · affected: Cisco IOS XE Software (50 versions) · updated 2021-03-24 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-xe-evss-code-exe-8cw5VSvw)\n\n**Cisco IOS XE Software Easy Virtual Switching System Arbitrary Code Execution Vulnerability**. Released 2021-03-24.\n\nAffected:\n\n- Cisco IOS XE Software 3.6.0E\n- Cisco IOS XE Software 3.6.1E\n- Cisco IOS XE Software 3.7.0E\n- Cisco IOS XE Software 3.6.0bE\n- Cisco IOS XE Software 3.7.1E\n- Cisco IOS XE Software 3.7.2E\n- Cisco IOS XE Software 3.6.2E\n- Cisco IOS XE Software 3.6.3E\n- Cisco IOS XE Software 3.6.4E\n- Cisco IOS XE Software 3.7.3E\n- Cisco IOS XE Software 3.8.0E\n- Cisco IOS XE Software 3.8.1E\n- Cisco IOS XE Software 3.6.5E\n- Cisco IOS XE Software 3.7.4E\n- Cisco IOS XE Software 3.9.0E\n- Cisco IOS XE Software 3.8.2E\n- Cisco IOS XE Software 3.7.5E\n- Cisco IOS XE Software 3.6.6E\n- Cisco IOS XE Software 3.8.3E\n- Cisco IOS XE Software 3.6.5aE\n- Cisco IOS XE Software 3.6.5bE\n- Cisco IOS XE Software 3.9.1E\n- Cisco IOS XE Software 3.8.4E\n- Cisco IOS XE Software 3.6.7E\n- Cisco IOS XE Software 3.9.2E\n- Cisco IOS XE Software 3.8.5E\n- Cisco IOS XE Software 3.10.0E\n- Cisco IOS XE Software 3.9.2bE\n- Cisco IOS XE Software 3.10.1E\n- Cisco IOS XE Software 3.6.8E\n- Cisco IOS XE Software 3.8.5aE\n- Cisco IOS XE Software 3.10.0cE\n- Cisco IOS XE Software 3.8.6E\n- Cisco IOS XE Software 3.10.2E\n- Cisco IOS XE Software 3.6.9E\n- Cisco IOS XE Software 3.10.1aE\n- Cisco IOS XE Software 3.8.7E\n- Cisco IOS XE Software 3.10.1sE\n- Cisco IOS XE Software 3.11.0E\n- Cisco IOS XE Software 3.6.10E\n\n## Remediation\n\nCisco has released software updates that address this vulnerability. https://software.cisco.com","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":44.6,"likelihood":0.7,"exploitation":0,"ransomware":0},"changes":[]}