{"schema_version":"public-product-v1.1","generated_at":"2026-07-21T10:31:43Z","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-iosxesdwan-rbuffover-vE2OB6tp","slug":"cisco-sa-iosxesdwan-rbuffover-ve2ob6tp","vendor":"Cisco","title":"Cisco IOS XE SD-WAN Software Buffer Overflow Vulnerability","summary":"A vulnerability in the vDaemon process in Cisco IOS XE SD-WAN Software could allow an unauthenticated, remote attacker to cause a buffer overflow on an affected device. This vulnerability is due to insufficient bounds checking when an affected device processes traffic. An attacker could exploit this vulnerability by sending crafted traffic to the device. A successful exploit could allow the attacker to cause a buffer overflow and possibly execute arbitrary commands with root-level privileges, or cause the device to reload, which could result in a denial of service condition. 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-iosxesdwan-rbuffover-vE2OB6tp This advisory is part of the September 2021 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.","severity":"Critical","published_at":"2021-09-22T16:00:00Z","updated_at":"2021-09-22T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp","csaf_url":"https://sec.cloudapps.cisco.com/security/center/contentjson/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp/csaf/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp.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":6,"public_evidence_count":6,"kev_count":0,"highest_epss":0.02629},"cves":[{"id":"CVE-2021-34727","kev":false,"epss":{"score":0.02629,"percentile":0.83831,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"}}],"public_evidence":[{"product":{"name":"Cisco Cloud Services Router 1000V Series","slug":"cisco-cloud-services-router-1000v-series","vendor":"Cisco"},"cve":{"id":"CVE-2021-34727"},"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":"2026-07-20T00:54:10Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco IOS XE Catalyst SD-WAN 16.11.1a when installed on Cisco Cloud Services Router 1000V Series; Cisco IOS XE Catalyst SD-WAN 16.11.1b when installed on Cisco Cloud Services Router 1000V Series; Cisco IOS XE Catalyst SD-WAN 16.12.1b when installed on Cisco Cloud Services Router 1000V Series; Cisco IOS XE Catalyst SD-WAN 16.12.1d when installed on Cisco Cloud Services Router 1000V Series; Cisco IOS XE Catalyst SD-WAN 16.12.1e when installed on Cisco Cloud Services Router 1000V Series; Cisco IOS XE Catalyst SD-WAN 16.12.2r when installed on Cisco Cloud Services Router 1000V Series; Cisco IOS XE Catalyst SD-WAN 16.12.3 when installed on Cisco Cloud Services Router 1000V Series","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":0.02629,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2021-09-22T16:00:00Z","updated_at":"2021-09-22T16:00:00Z","advisory_updated_at":"2021-09-22T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp"},"row_display_order":1},{"product":{"name":"Cisco 1000 Series Integrated Services Routers","slug":"cisco-1000-series-integrated-services-routers","vendor":"Cisco"},"cve":{"id":"CVE-2021-34727"},"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":"2026-07-20T00:54:10Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco IOS XE Catalyst SD-WAN 16.11.1a when installed on Cisco 1000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.11.1b when installed on Cisco 1000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1b when installed on Cisco 1000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1d when installed on Cisco 1000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1e when installed on Cisco 1000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.2r when installed on Cisco 1000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.3 when installed on Cisco 1000 Series Integrated Services Routers","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":0.02629,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2021-09-22T16:00:00Z","updated_at":"2021-09-22T16:00:00Z","advisory_updated_at":"2021-09-22T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp"},"row_display_order":2},{"product":{"name":"Cisco ASR 1000 Series Aggregation Services Routers","slug":"cisco-asr-1000-series-aggregation-services-routers","vendor":"Cisco"},"cve":{"id":"CVE-2021-34727"},"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":"2026-07-20T00:54:10Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco IOS XE Catalyst SD-WAN 16.11.1a when installed on Cisco ASR 1000 Series Aggregation Services Routers; Cisco IOS XE Catalyst SD-WAN 16.11.1b when installed on Cisco ASR 1000 Series Aggregation Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1b when installed on Cisco ASR 1000 Series Aggregation Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1d when installed on Cisco ASR 1000 Series Aggregation Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1e when installed on Cisco ASR 1000 Series Aggregation Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.2r when installed on Cisco ASR 1000 Series Aggregation Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.3 when installed on Cisco ASR 1000 Series Aggregation Services Routers","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":0.02629,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2021-09-22T16:00:00Z","updated_at":"2021-09-22T16:00:00Z","advisory_updated_at":"2021-09-22T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp"},"row_display_order":3},{"product":{"name":"Cisco 4000 Series Integrated Services Routers","slug":"cisco-4000-series-integrated-services-routers","vendor":"Cisco"},"cve":{"id":"CVE-2021-34727"},"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":"2026-07-20T00:54:10Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco IOS XE Catalyst SD-WAN 16.11.1a when installed on Cisco 4000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.11.1b when installed on Cisco 4000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.11.1f when installed on Cisco 4000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1b when installed on Cisco 4000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1d when installed on Cisco 4000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1e when installed on Cisco 4000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.2r when installed on Cisco 4000 Series Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.3 when installed on Cisco 4000 Series Integrated Services Routers","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":0.02629,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2021-09-22T16:00:00Z","updated_at":"2021-09-22T16:00:00Z","advisory_updated_at":"2021-09-22T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp"},"row_display_order":4},{"product":{"name":"Cisco Integrated Services Virtual Router","slug":"cisco-integrated-services-virtual-router","vendor":"Cisco"},"cve":{"id":"CVE-2021-34727"},"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":"2026-07-20T00:54:10Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco IOS XE Catalyst SD-WAN 16.11.1a when installed on Cisco Integrated Services Virtual Router; Cisco IOS XE Catalyst SD-WAN 16.11.1b when installed on Cisco Integrated Services Virtual Router; Cisco IOS XE Catalyst SD-WAN 16.12.1b when installed on Cisco Integrated Services Virtual Router; Cisco IOS XE Catalyst SD-WAN 16.12.1d when installed on Cisco Integrated Services Virtual Router; Cisco IOS XE Catalyst SD-WAN 16.12.1e when installed on Cisco Integrated Services Virtual Router; Cisco IOS XE Catalyst SD-WAN 16.12.2r when installed on Cisco Integrated Services Virtual Router; Cisco IOS XE Catalyst SD-WAN 16.12.3 when installed on Cisco Integrated Services Virtual Router","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":0.02629,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2021-09-22T16:00:00Z","updated_at":"2021-09-22T16:00:00Z","advisory_updated_at":"2021-09-22T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp"},"row_display_order":5},{"product":{"name":"Cisco 1100 Series Industrial Integrated Services Routers","slug":"cisco-1100-series-industrial-integrated-services-routers","vendor":"Cisco"},"cve":{"id":"CVE-2021-34727"},"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":"2026-07-20T00:54:10Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco IOS XE Catalyst SD-WAN 16.12.1b when installed on Cisco 1100 Series Industrial Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1d when installed on Cisco 1100 Series Industrial Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.1e when installed on Cisco 1100 Series Industrial Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.2r when installed on Cisco 1100 Series Industrial Integrated Services Routers; Cisco IOS XE Catalyst SD-WAN 16.12.3 when installed on Cisco 1100 Series Industrial Integrated Services Routers","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":0.02629,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2021-09-22T16:00:00Z","updated_at":"2021-09-22T16:00:00Z","advisory_updated_at":"2021-09-22T16:00:00Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxesdwan-rbuffover-vE2OB6tp"},"row_display_order":6}]}