{"schema_version":"public-product-v1.1","generated_at":"2026-07-21T05:35:56Z","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-bgp-iefab-3hb2pwtx","slug":"cisco-sa-bgp-iefab-3hb2pwtx","vendor":"Cisco","title":"Cisco Nexus 3000 and 9000 Series Switches Border Gateway Protocol Denial of Service Vulnerability","summary":"A vulnerability in the Border Gateway Protocol (BGP) enforce-first-as feature of Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, remote attacker to trigger BGP peer flaps, resulting in a denial of service (DoS) condition. This vulnerability is due to incorrect parsing of a transitive BGP attribute. An attacker could exploit this vulnerability by sending a crafted BGP update through an established BGP peer session. If the update propagates to an affected device, it could cause the device to drop the BGP session and flap with the BGP peer that is forwarding this update, resulting in a DoS condition. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgp-iefab-3hb2pwtx","severity":"Medium","published_at":"2026-05-20T16:00:00Z","updated_at":"2026-05-20T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgp-iefab-3hb2pwtx","csaf_url":"https://sec.cloudapps.cisco.com/security/center/contentjson/CiscoSecurityAdvisory/cisco-sa-bgp-iefab-3hb2pwtx/csaf/cisco-sa-bgp-iefab-3hb2pwtx.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":0.00467},"cves":[{"id":"CVE-2026-20171","kev":false,"epss":{"score":0.00467,"percentile":0.37548,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"}}],"public_evidence":[{"product":{"name":"Cisco Nexus 3000 Series Switches","slug":"cisco-nexus-3000-series-switches","vendor":"Cisco"},"cve":{"id":"CVE-2026-20171"},"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":"2026-07-19T21:34:31Z","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 10.2(1) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(2) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(3) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(3t) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(3v) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(4) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(5) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(6) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(7) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(8) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.2(9) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(1) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(2) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(3) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(4) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(4a) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(5) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(6) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(7) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.3(8) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.4(1) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.4(2) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.4(3) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.4(4) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.4(5) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.4(6) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.5(1) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.5(2) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.5(3) when installed on Cisco Nexus 3000 Series Switches; Cisco NX-OS Software 10.6(1) 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":0.00467,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2026-05-20T16:00:00Z","updated_at":"2026-05-20T16:00:00Z","advisory_updated_at":"2026-05-20T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgp-iefab-3hb2pwtx","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgp-iefab-3hb2pwtx"},"row_display_order":1},{"product":{"name":"Cisco Nexus 9000 Series Switches","slug":"cisco-nexus-9000-series-switches","vendor":"Cisco"},"cve":{"id":"CVE-2026-20171"},"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":"2026-07-19T21:34:31Z","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 10.2(1) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(1q) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(2) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(2a) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(3) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(4) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(5) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(6) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(7) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(8) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.2(9) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(1) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(2) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(3) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(3o) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(3p) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(3q) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(3r) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(3w) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(3x) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(4) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(4a) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(4g) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(4h) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(5) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(6) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(7) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(8) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(99w) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.3(99x) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.4(1) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.4(2) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.4(3) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.4(4) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.4(4g) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.4(5) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.4(6) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.5(1) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.5(2) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.5(3) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.5(3e) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.5(3o) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.5(3p) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.5(3s) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.5(3t) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.6(1) when installed on Cisco Nexus 9000 Series Switches; Cisco NX-OS Software 10.6(1s) 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":0.00467,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2026-05-20T16:00:00Z","updated_at":"2026-05-20T16:00:00Z","advisory_updated_at":"2026-05-20T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgp-iefab-3hb2pwtx","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgp-iefab-3hb2pwtx"},"row_display_order":2}]}