{"schema_version":"public-product-v1.1","generated_at":"2026-07-21T10:41:31Z","exposure_verdict":"not_assessed","verdict_reason":"Public evidence does not evaluate exact release, platform, enabled features, configuration, compensating controls, or live exposure.","advisory":{"id":"cisco-sa-nxos-ngoam-dos-LTDb9Hv","slug":"cisco-sa-nxos-ngoam-dos-ltdb9hv","vendor":"Cisco","title":"Cisco NX-OS Software VXLAN OAM (NGOAM) Denial of Service Vulnerability","summary":"A vulnerability in the VXLAN Operation, Administration, and Maintenance (OAM) feature of Cisco NX-OS Software, known as NGOAM, could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of specific packets with a Transparent Interconnection of Lots of Links (TRILL) OAM EtherType. An attacker could exploit this vulnerability by sending crafted packets, including the TRILL OAM EtherType of 0x8902, to a device that is part of a VXLAN Ethernet VPN (EVPN) fabric. A successful exploit could allow the attacker to cause an affected device to experience high CPU usage and consume excessive system resources, which may result in overall control plane instability and cause the affected device to reload. Note: The NGOAM feature is disabled by default. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ngoam-dos-LTDb9Hv This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.","severity":"High","published_at":"2021-08-25T16:00:00Z","updated_at":"2021-08-25T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ngoam-dos-LTDb9Hv","csaf_url":"https://sec.cloudapps.cisco.com/security/center/contentjson/CiscoSecurityAdvisory/cisco-sa-nxos-ngoam-dos-LTDb9Hv/csaf/cisco-sa-nxos-ngoam-dos-LTDb9Hv.json","exposure_verdict":"not_assessed","verdict_reason":"Public evidence does not evaluate exact release, platform, enabled features, configuration, compensating controls, or live exposure."},"freshness":{"last_source_refreshed_at":"2026-07-21T05:16:34Z","latest_source_refresh_at":"2026-07-21T05:16:34Z","oldest_source_refresh_at":"2026-07-21T03:00:03Z","all_sources_fresh":true,"sources":[{"source":"cisco_advisories","label":"Cisco advisories","last_success_at":"2026-07-21T03:00:03Z","stale":false},{"source":"cisco_csaf","label":"Cisco CSAF","last_success_at":"2026-07-21T05:14:24Z","stale":false},{"source":"nvd_cves","label":"NVD CVEs","last_success_at":"2026-07-21T05:16:30Z","stale":false},{"source":"cisa_kev","label":"CISA KEV","last_success_at":"2026-07-21T05:16:31Z","stale":false},{"source":"first_epss","label":"EPSS","last_success_at":"2026-07-21T05:16:34Z","stale":false}]},"summary":{"cve_count":1,"visible_product_count":2,"public_evidence_count":2,"kev_count":0,"highest_epss":0.01681},"cves":[{"id":"CVE-2021-1587","kev":false,"epss":{"score":0.01681,"percentile":0.74371,"score_date":"2026-07-19","updated_at":"2026-07-20T05:46:48Z"}}],"public_evidence":[{"product":{"name":"Cisco Nexus 3000 Series Switches","slug":"cisco-nexus-3000-series-switches","vendor":"Cisco"},"cve":{"id":"CVE-2021-1587"},"evidence_type":"structured_affected","evidence_label":{"scope":"CSAF product evidence","label":"product_status known affected"},"evidence_source":"Cisco CSAF","source":"Cisco CSAF","source_document_fetched_at":"2026-07-20T04:11:45Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco NX-OS Software 10.1(1) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.2(1) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.2(2) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.2(2t) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.2(2v) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.2(3) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.2(3y) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.2(4) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(1) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(2) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(3) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(4) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(5) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(5w) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(6) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(7) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(7a) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 9.3(7k) when installed on Cisco Nexus 3000 Series Switches","exposure_verdict":"not_assessed","verdict_reason":"Public evidence does not evaluate exact release, platform, enabled features, configuration, compensating controls, or live exposure.","exposure_verdict_reason":"Public evidence does not evaluate exact release, platform, enabled features, configuration, compensating controls, or live exposure.","kev":false,"epss":{"score":0.01681,"score_date":"2026-07-19","updated_at":"2026-07-20T05:46:48Z"},"published_at":"2021-08-25T16:00:00Z","updated_at":"2021-08-25T16:00:00Z","advisory_updated_at":"2021-08-25T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ngoam-dos-LTDb9Hv","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ngoam-dos-LTDb9Hv"},"row_display_order":1},{"product":{"name":"Cisco Nexus 9000 Series Switches","slug":"cisco-nexus-9000-series-switches","vendor":"Cisco"},"cve":{"id":"CVE-2021-1587"},"evidence_type":"structured_affected","evidence_label":{"scope":"CSAF product evidence","label":"product_status known affected"},"evidence_source":"Cisco CSAF","source":"Cisco CSAF","source_document_fetched_at":"2026-07-20T04:11:45Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco NX-OS Software 10.1(1) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.2(1) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.2(2) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.2(3) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.2(3y) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.2(4) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(1) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(1z) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(2) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(3) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(4) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(5) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(5w) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(6) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(7) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(7a) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 9.3(7k) when installed on Cisco Nexus 9000 Series Switches","exposure_verdict":"not_assessed","verdict_reason":"Public evidence does not evaluate exact release, platform, enabled features, configuration, compensating controls, or live exposure.","exposure_verdict_reason":"Public evidence does not evaluate exact release, platform, enabled features, configuration, compensating controls, or live exposure.","kev":false,"epss":{"score":0.01681,"score_date":"2026-07-19","updated_at":"2026-07-20T05:46:48Z"},"published_at":"2021-08-25T16:00:00Z","updated_at":"2021-08-25T16:00:00Z","advisory_updated_at":"2021-08-25T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ngoam-dos-LTDb9Hv","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ngoam-dos-LTDb9Hv"},"row_display_order":2}]}