{"schema_version":"public-product-v1.1","generated_at":"2026-07-21T09:58:31Z","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-iosxr-ipxe-sigbypass-pymfyqgB","slug":"cisco-sa-iosxr-ipxe-sigbypass-pymfyqgb","vendor":"Cisco","title":"Cisco IOS XR Software iPXE Boot Signature Bypass Vulnerability","summary":"A vulnerability in the iPXE boot function of Cisco IOS XR software could allow an authenticated, local attacker to install an unverified software image on an affected device. This vulnerability is due to insufficient image verification. An attacker could exploit this vulnerability by manipulating the boot parameters for image verification during the iPXE boot process on an affected device. A successful exploit could allow the attacker to boot an unverified software image on the affected device.  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-iosxr-ipxe-sigbypass-pymfyqgB This advisory is part of the September 2023 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication.","severity":"Medium","published_at":"2023-09-13T16:00:00Z","updated_at":"2024-08-07T15:55:33Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-ipxe-sigbypass-pymfyqgB","csaf_url":"https://sec.cloudapps.cisco.com/security/center/contentjson/CiscoSecurityAdvisory/cisco-sa-iosxr-ipxe-sigbypass-pymfyqgB/csaf/cisco-sa-iosxr-ipxe-sigbypass-pymfyqgB.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":1,"public_evidence_count":1,"kev_count":0,"highest_epss":0.00095},"cves":[{"id":"CVE-2023-20236","kev":false,"epss":{"score":0.00095,"percentile":0.00812,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"}}],"public_evidence":[{"product":{"name":"Cisco IOS XR Software","slug":"cisco-ios-xr-software","vendor":"Cisco"},"cve":{"id":"CVE-2023-20236"},"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":"2026-07-20T03:57:55Z","csaf_status":"known_affected","csaf_product_status":"known_affected","csaf_product_status_path":"vulnerabilities[].product_status.known_affected","raw_product_name":"Cisco IOS XR Software","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":0.00095,"score_date":"2026-07-20","updated_at":"2026-07-21T05:16:34Z"},"published_at":"2023-09-13T16:00:00Z","updated_at":"2024-08-07T15:55:33Z","advisory_updated_at":"2024-08-07T15:55:33Z","source_url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-ipxe-sigbypass-pymfyqgB","remediation":{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-ipxe-sigbypass-pymfyqgB"},"row_display_order":1}]}