{"schema":"threatline.record/2","record":{"id":"CVE-2023-4966","aliases":[],"summary":"Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability","details":"Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that allows for sensitive information disclosure when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server.","categories":["Network & edge"],"product":"NetScaler ADC and NetScaler Gateway","vendor":"Citrix","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"NetScaler ADC","vendor":"Citrix","versions":[{"lessThan":"8.50","status":"affected","version":"14.1","versionType":"patch"},{"lessThan":"49.15","status":"affected","version":"13.1","versionType":"patch"},{"lessThan":"92.19","status":"affected","version":"13.0","versionType":"patch"},{"lessThan":"37.164","status":"affected","version":"13.1-FIPS","versionType":"patch"},{"lessThan":"55.300","status":"affected","version":"12.1-FIPS","versionType":"patch"},{"lessThan":"55.300","status":"affected","version":"12.1-NDcPP","versionType":"patch"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"NetScaler Gateway","vendor":"Citrix","versions":[{"lessThan":"8.50","status":"affected","version":"14.1","versionType":"patch"},{"lessThan":"49.15","status":"affected","version":"13.1","versionType":"patch"},{"lessThan":"92.19","status":"affected","version":"13.0","versionType":"patch"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"NetScaler ADC","ecosystem":null},"version":"8.50","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"NetScaler ADC","ecosystem":null},"version":"49.15","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"NetScaler ADC","ecosystem":null},"version":"92.19","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"NetScaler ADC","ecosystem":null},"version":"37.164","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"NetScaler ADC","ecosystem":null},"version":"55.300","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"NetScaler Gateway","ecosystem":null},"version":"8.50","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"NetScaler Gateway","ecosystem":null},"version":"49.15","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","source_modified_at":"2026-07-31T03:55:28.627Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"NetScaler Gateway","ecosystem":null},"version":"92.19","basis":"first unaffected version stated in the CVE record"}],"cvss":9.4,"severity":"Critical","kev":{"listed":true,"date_added":"2023-10-18","due_date":"2023-11-08","required_action":"Apply mitigations and kill all active and persistent sessions per vendor instructions [https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/] OR discontinue use of the product if mitigations are unavailable.","ransomware_campaign_use":"Known"},"epss":{"probability":0.99999,"percentile":0.99997,"score_date":"2026-10-23"},"published_at":"2023-10-10T13:12:17.644Z","modified_at":"2026-07-31T03:55:28.627Z","provenance":[{"source":"CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23T17:00:09.9001Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2023-4966","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-07-31T03:55:28.627Z"},{"source":"Metasploit","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/http/citrix_bleed_cve_2023_4966.rb","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2023-10-25"},{"source":"Nuclei","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2023/CVE-2023-4966.yaml","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":null},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2023-4966","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CISA KEV","CVE List","Metasploit","Nuclei","EPSS"],"references":[{"url":"https://www.netscaler.com/blog/news/cve-2023-4966-critical-security-update-now-available-for-netscaler-adc-and-netscaler-gateway/, https://support.citrix.com/article/CTX579459/netscaler-adc-and-netscaler-gateway-security-bulletin-for-cve20234966-and-cve20234967","source":"CISA KEV"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-4966","source":"CISA KEV"},{"source":"CVE List","url":"https://support.citrix.com/article/CTX579459","tags":["x_transferred"]},{"source":"CVE List","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4966","tags":["government-resource"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"active","automatable":"yes","technical_impact":"total","assessed_at":"2023-10-10T00:00:00+00:00"},"exploits":[{"source":"Metasploit","kind":"Auxiliary module","name":"Citrix ADC (NetScaler) Bleed Scanner","url":"https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/http/citrix_bleed_cve_2023_4966.rb","date":"2023-10-25","added":"2023-10-27","check":false},{"source":"Nuclei","kind":"Scanner template","name":"Citrix Bleed - Leaking Session Tokens","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2023/CVE-2023-4966.yaml"}],"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-07-31T03:55:28.627Z","content_hash":"bd87fd15ccdc88a1e6d1e715e8673dfcadcc7b4d6eca5d5e992bd712517ed828"}}