{"id":"CVE-2025-20241","state":"PUBLISHED","title":"Cisco Nexus 3000 and 9000 Series Switches IS-IS Protocol <TBD> Denial of Service Vulnerability","description":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) feature of Cisco NX-OS Software for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the IS-IS process to unexpectedly restart, which could cause an affected device to reload.\r\n\r\nThis 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. A successful exploit could allow the attacker to cause the unexpected restart of the IS-IS process, which could cause the affected device to reload, resulting in a denial of service (DoS) condition.\r\nNote: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device.","publishedAt":"2025-08-27T16:23:55.242Z","updatedAt":"2025-08-27T18:18:32.250Z","severity":{"score":7.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","source":"cisco"},"assigner":"cisco","products":["Cisco Cisco NX-OS Software"],"affected":[{"vendor":"Cisco","product":"Cisco NX-OS Software","defaultStatus":"unknown","versions":[{"version":"9.2(3)","status":"affected"},{"version":"7.0(3)I5(2)","status":"affected"},{"version":"6.0(2)A8(7a)","status":"affected"},{"version":"7.0(3)I4(5)","status":"affected"},{"version":"7.0(3)I4(6)","status":"affected"},{"version":"7.0(3)I4(3)","status":"affected"},{"version":"9.2(2v)","status":"affected"},{"version":"7.0(3)I4(7)","status":"affected"},{"version":"7.0(3)I4(1)","status":"affected"},{"version":"7.0(3)I4(8)","status":"affected"},{"version":"7.0(3)I4(2)","status":"affected"},{"version":"6.0(2)A8(11)","status":"affected"},{"version":"9.2(1)","status":"affected"},{"version":"9.2(2t)","status":"affected"},{"version":"9.2(3y)","status":"affected"},{"version":"7.0(3)I4(1t)","status":"affected"},{"version":"7.0(3)I7(6z)","status":"affected"},{"version":"9.3(2)","status":"affected"},{"version":"7.0(3)F3(3)","status":"affected"},{"version":"7.0(3)I7(3z)","status":"affected"},{"version":"7.0(3)IM7(2)","status":"affected"},{"version":"6.0(2)A8(11b)","status":"affected"},{"version":"7.0(3)I7(5a)","status":"affected"},{"version":"7.0(3)I6(1)","status":"affected"},{"version":"7.0(3)I5(3b)","status":"affected"},{"version":"9.2(4)","status":"affected"},{"version":"6.0(2)A8(10)","status":"affected"},{"version":"6.0(2)A8(2)","status":"affected"},{"version":"7.0(3)IC4(4)","status":"affected"},{"version":"7.0(3)F3(3c)","status":"affected"},{"version":"7.0(3)F3(1)","status":"affected"},{"version":"7.0(3)F3(5)","status":"affected"},{"version":"7.0(3)I7(2)","status":"affected"},{"version":"7.0(3)I5(3)","status":"affected"},{"version":"7.0(3)I7(3)","status":"affected"},{"version":"6.0(2)A8(6)","status":"affected"},{"version":"7.0(3)I6(2)","status":"affected"},{"version":"6.0(2)A8(5)","status":"affected"},{"version":"9.3(1)","status":"affected"},{"version":"6.0(2)A8(7)","status":"affected"},{"version":"7.0(3)I7(6)","status":"affected"},{"version":"6.0(2)A8(11a)","status":"affected"},{"version":"7.0(3)I4(8z)","status":"affected"},{"version":"7.0(3)I4(9)","status":"affected"},{"version":"7.0(3)I7(4)","status":"affected"},{"version":"7.0(3)I7(7)","status":"affected"},{"version":"6.0(2)A8(9)","status":"affected"},{"version":"6.0(2)A8(1)","status":"affected"},{"version":"6.0(2)A8(10a)","status":"affected"},{"version":"7.0(3)I5(1)","status":"affected"},{"version":"9.3(1z)","status":"affected"},{"version":"9.2(2)","status":"affected"},{"version":"7.0(3)F3(4)","status":"affected"},{"version":"7.0(3)I4(8b)","status":"affected"},{"version":"6.0(2)A8(3)","status":"affected"},{"version":"7.0(3)I4(6t)","status":"affected"},{"version":"7.0(3)I5(3a)","status":"affected"},{"version":"6.0(2)A8(8)","status":"affected"},{"version":"7.0(3)I7(5)","status":"affected"},{"version":"7.0(3)F3(3a)","status":"affected"},{"version":"6.0(2)A8(4)","status":"affected"},{"version":"7.0(3)I4(8a)","status":"affected"},{"version":"7.0(3)F3(2)","status":"affected"},{"version":"7.0(3)I4(4)","status":"affected"},{"version":"7.0(3)I7(1)","status":"affected"},{"version":"7.0(3)IA7(2)","status":"affected"},{"version":"7.0(3)IA7(1)","status":"affected"},{"version":"6.0(2)A8(7b)","status":"affected"},{"version":"6.0(2)A8(4a)","status":"affected"},{"version":"9.3(3)","status":"affected"},{"version":"7.0(3)I7(8)","status":"affected"},{"version":"9.3(4)","status":"affected"},{"version":"9.3(5)","status":"affected"},{"version":"7.0(3)I7(9)","status":"affected"},{"version":"9.3(6)","status":"affected"},{"version":"10.1(2)","status":"affected"},{"version":"10.1(1)","status":"affected"},{"version":"9.3(5w)","status":"affected"},{"version":"9.3(7)","status":"affected"},{"version":"9.3(7k)","status":"affected"},{"version":"7.0(3)I7(9w)","status":"affected"},{"version":"10.2(1)","status":"affected"},{"version":"9.3(7a)","status":"affected"},{"version":"9.3(8)","status":"affected"},{"version":"7.0(3)I7(10)","status":"affected"},{"version":"10.2(1q)","status":"affected"},{"version":"10.2(2)","status":"affected"},{"version":"9.3(9)","status":"affected"},{"version":"10.1(2t)","status":"affected"},{"version":"10.2(3)","status":"affected"},{"version":"10.2(3t)","status":"affected"},{"version":"9.3(10)","status":"affected"},{"version":"10.2(2a)","status":"affected"},{"version":"10.3(1)","status":"affected"},{"version":"10.2(4)","status":"affected"},{"version":"10.3(2)","status":"affected"},{"version":"9.3(11)","status":"affected"},{"version":"10.3(3)","status":"affected"},{"version":"10.2(5)","status":"affected"},{"version":"9.3(12)","status":"affected"},{"version":"10.2(3v)","status":"affected"},{"version":"10.4(1)","status":"affected"},{"version":"10.3(99w)","status":"affected"},{"version":"10.2(6)","status":"affected"},{"version":"10.3(3w)","status":"affected"},{"version":"10.3(99x)","status":"affected"},{"version":"10.3(3o)","status":"affected"},{"version":"10.3(4)","status":"affected"},{"version":"10.3(3p)","status":"affected"},{"version":"10.3(4a)","status":"affected"},{"version":"10.4(2)","status":"affected"},{"version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Nexus 3000 and 9000 Series Switches IS-IS Protocol <TBD> Denial of Service Vulnerability","descriptions":[{"lang":"en","value":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) feature of Cisco NX-OS Software for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the IS-IS process to unexpectedly restart, which could cause an affected device to reload.\r\n\r\nThis 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. A successful exploit could allow the attacker to cause the unexpected restart of the IS-IS process, which could cause the affected device to reload, resulting in a denial of service (DoS) condition.\r\nNote: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device."}],"affected":[{"vendor":"Cisco","product":"Cisco NX-OS 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Optimization Removal or Modification of Security-critical Code","type":"cwe"}]}],"providerMetadata":{"shortName":"cisco","orgId":"d1c1063e-7a18-46af-9102-31f8928bc633","dateUpdated":"2025-08-27T16:23:55.242Z"},"exploits":[{"lang":"en","value":"The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory."}],"source":{"advisory":"cisco-sa-n39k-isis-dos-JhJA8Rfx","discovery":"INTERNAL","defects":["CSCwn49153"]}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2025-08-27T18:18:19.522793Z","id":"CVE-2025-20241","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-08-27T18:18:32.250Z"}}]}}}