{"api_version":"1","generated_at":"2026-07-13T22:50:46+00:00","cve":"CVE-2026-20074","urls":{"html":"https://cve.report/CVE-2026-20074","api":"https://cve.report/api/cve/CVE-2026-20074.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-20074","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-20074"},"summary":{"title":"Cisco IOS XR Software Multi-Instance Intermediate System-to-Intermediate System Denial of Service Vulnerability","description":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly.\r\n\r\nThis vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and 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 and must have formed an adjacency.  ","state":"PUBLISHED","assigner":"cisco","published_at":"2026-03-11 17:16:55","updated_at":"2026-07-08 19:07:12"},"problem_types":["CWE-1287","CWE-1287 Improper Validation of Specified Type of Input"],"metrics":[{"version":"3.1","source":"psirt@cisco.com","type":"Secondary","score":"7.4","severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","baseScore":7.4,"baseSeverity":"HIGH","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSSV3_1","score":"7.4","severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","data":{"attackComplexity":"LOW","attackVector":"ADJACENT_NETWORK","availabilityImpact":"HIGH","baseScore":7.4,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK","name":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK","refsource":"psirt@cisco.com","tags":["Mitigation","Vendor Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-20074","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-20074","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.8.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.9.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.10.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.8.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.8.22","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.9.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.11.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.9.21","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.10.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.1.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.11.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.2.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.1.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.2.11","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.3.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.4.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.2.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.8.23","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 7.11.21","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.2.20","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.3.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.4.10","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 25.1.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.4.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.3.20","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.4.15","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 25.2.1","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 25.1.2","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.3.30","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.4.30","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 24.2.21","platforms":[]},{"source":"CNA","vendor":"Cisco","product":"Cisco IOS XR Software","version":"affected 25.2.15","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[{"source":"CNA","title":"","value":"The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.","time":"","lang":"en"}],"credits":[],"nvd_cpes":[{"cve_year":"2026","cve_id":"20074","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"cisco","cpe5":"ios_xr","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2026","cve_id":"20074","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"cisco","cpe5":"ios_xr","cpe6":"25.3.0","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"20074","cve":"CVE-2026-20074","epss":"0.001600000","percentile":"0.055570000","score_date":"2026-07-10","updated_at":"2026-07-11 00:11:17"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-20074","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-03-11T17:04:46.266844Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-03-11T17:20:21.640Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"defaultStatus":"unknown","product":"Cisco IOS XR Software","vendor":"Cisco","versions":[{"status":"affected","version":"7.8.1"},{"status":"affected","version":"7.9.1"},{"status":"affected","version":"7.10.1"},{"status":"affected","version":"7.8.2"},{"status":"affected","version":"7.8.22"},{"status":"affected","version":"7.9.2"},{"status":"affected","version":"7.11.1"},{"status":"affected","version":"7.9.21"},{"status":"affected","version":"7.10.2"},{"status":"affected","version":"24.1.1"},{"status":"affected","version":"7.11.2"},{"status":"affected","version":"24.2.1"},{"status":"affected","version":"24.1.2"},{"status":"affected","version":"24.2.11"},{"status":"affected","version":"24.3.1"},{"status":"affected","version":"24.4.1"},{"status":"affected","version":"24.2.2"},{"status":"affected","version":"7.8.23"},{"status":"affected","version":"7.11.21"},{"status":"affected","version":"24.2.20"},{"status":"affected","version":"24.3.2"},{"status":"affected","version":"24.4.10"},{"status":"affected","version":"25.1.1"},{"status":"affected","version":"24.4.2"},{"status":"affected","version":"24.3.20"},{"status":"affected","version":"24.4.15"},{"status":"affected","version":"25.2.1"},{"status":"affected","version":"25.1.2"},{"status":"affected","version":"24.3.30"},{"status":"affected","version":"24.4.30"},{"status":"affected","version":"24.2.21"},{"status":"affected","version":"25.2.15"}]}],"descriptions":[{"lang":"en","value":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly.\r\n\r\nThis vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and 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 and must have formed an adjacency.  "}],"exploits":[{"lang":"en","value":"The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory."}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"ADJACENT_NETWORK","availabilityImpact":"HIGH","baseScore":7.4,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","version":"3.1"},"format":"cvssV3_1"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1287","description":"Improper Validation of Specified Type of Input","lang":"en","type":"cwe"}]}],"providerMetadata":{"dateUpdated":"2026-03-11T16:31:14.712Z","orgId":"d1c1063e-7a18-46af-9102-31f8928bc633","shortName":"cisco"},"references":[{"name":"cisco-sa-isis-dos-kDMxpSzK","url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK"}],"source":{"advisory":"cisco-sa-isis-dos-kDMxpSzK","defects":["CSCwq71827"],"discovery":"INTERNAL"},"title":"Cisco IOS XR Software Multi-Instance Intermediate System-to-Intermediate System Denial of Service Vulnerability"}},"cveMetadata":{"assignerOrgId":"d1c1063e-7a18-46af-9102-31f8928bc633","assignerShortName":"cisco","cveId":"CVE-2026-20074","datePublished":"2026-03-11T16:31:14.712Z","dateReserved":"2025-10-08T11:59:15.362Z","dateUpdated":"2026-03-11T17:20:21.640Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-03-11 17:16:55","lastModifiedDate":"2026-07-08 19:07:12","problem_types":["CWE-1287","CWE-1287 Improper Validation of Specified Type of Input"],"metrics":{"cvssMetricV31":[{"source":"psirt@cisco.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","baseScore":7.4,"baseSeverity":"HIGH","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":2.8,"impactScore":4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-03-11T17:04:46.266844Z","id":"CVE-2026-20074","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*","versionStartIncluding":"7.8.0","versionEndExcluding":"25.2.2","matchCriteriaId":"8352E25F-6467-4428-B677-013F64C9F130"},{"vulnerable":true,"criteria":"cpe:2.3:o:cisco:ios_xr:25.3.0:*:*:*:*:*:*:*","matchCriteriaId":"1B34524C-985A-421D-91D8-3447294A44B3"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"20074","Ordinal":"1","Title":"Cisco IOS XR Software Multi-Instance Intermediate System-to-Inte","CVE":"CVE-2026-20074","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"20074","Ordinal":"1","NoteData":"A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly.\r\n\r\nThis vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and 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 and must have formed an adjacency.  ","Type":"Description","Title":"Cisco IOS XR Software Multi-Instance Intermediate System-to-Inte"}]}}}