{"id":"CVE-2024-20312","aliases":["EUVD-2024-18027","GHSA-h59x-f52x-4wxj"],"status":"published","title":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS...","description":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.\r\n\r This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.\r\n\r Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and have formed an adjacency.","severity":{"version":"3.1","score":7.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00256,"percentile":0.17347,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-476"],"published":"2024-03-27T16:56:42Z","modified":"2026-06-17T07:06:23Z","products":[{"vendor":"cisco","product":"cisco ios xe software"},{"vendor":"cisco","product":"ios"},{"vendor":"cisco","product":"ios_xe"}],"references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-sGjyOUHX","tags":["x_transferred","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-20312"},{"url":"https://github.com/advisories/GHSA-h59x-f52x-4wxj"}],"sources":{"cve":[{"id":"CVE-2024-20312","description":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.\r\n\r This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.\r\n\r Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and have formed an adjacency.","status":"published","published":"2024-03-27T16:56:42.49Z","modified":"2025-08-26T20:06:08.344Z","cvss":[{"version":"3.1","score":7.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-476"],"updated_at":"2026-11-02T14:33:56.868512Z"}],"euvd":[{"id":"EUVD-2024-18027","description":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.\r\n\r This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.\r\n\r Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and have formed an adjacency.","status":"published","published":"2024-03-27T16:56:42Z","modified":"2025-08-26T20:06:08Z","cvss":[{"version":"3.1","score":7.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T20:31:52.651465Z"}],"ghsa":[{"id":"GHSA-h59x-f52x-4wxj","title":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS...","description":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.\n\n This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.\n\n Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and have formed an adjacency.","status":"published","published":"2024-03-27T18:32:38Z","modified":"2024-03-27T18:32:45Z","cvss":[{"version":"3.1","score":7.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-476"],"updated_at":"2026-11-02T14:55:43.592151Z"}],"nvd":[{"id":"CVE-2024-20312","description":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.\r\n\r This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.\r\n\r Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and have formed an adjacency.","status":"published","published":"2024-03-27T17:15:52.69Z","modified":"2026-06-17T07:06:23.467Z","cvss":[{"version":"3.1","score":7.4,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-476"],"updated_at":"2026-11-02T14:09:44.124823Z"}]}}