{"cve":{"cve_id":"CVE-2026-56766","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":null,"epss_percentile":null,"epss_as_of":null,"description":"Hydra through 9.7, fixed in commit 9cc84c2, contains a stack buffer overflow in NTLM authentication across SMTP, POP3, IMAP, NNTP, HTTP, HTTP-Proxy, and HTTP-Proxy-Urlenum modules when processing malicious NTLM Type-2 challenges. A malicious server can send a crafted NTLM Type-2 challenge with an excessively long domain string, causing base64-encoded response data to overflow a 500-byte stack buffer by 18 to 330 bytes, enabling remote code execution on systems without stack protection.","published_at":"2026-06-25T18:01:07.362000Z","last_modified_at":null,"cvss_v3_score":8.8,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":8.6,"cvss_v4_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","cvss_v4_severity":"HIGH","ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-121"],"nvd_references":["https://github.com/vanhauser-thc/thc-hydra/commit/9cc84c20e75f5fef6bb1790bb9ada2afad2204e2","https://www.vulncheck.com/advisories/hydra-stack-buffer-overflow-in-ntlm-authentication-handler"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-28T17:55:42.709123Z","updated_at":"2026-06-28T23:30:57.805291Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"R","value_label":"Required"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":"4.0","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"AT","name":"Attack Requirements","value":"N","value_label":"None"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"A","value_label":"Active"},{"metric":"VC","name":"Confidentiality (Vulnerable System)","value":"H","value_label":"High"},{"metric":"VI","name":"Integrity (Vulnerable System)","value":"H","value_label":"High"},{"metric":"VA","name":"Availability (Vulnerable System)","value":"H","value_label":"High"},{"metric":"SC","name":"Confidentiality (Subsequent System)","value":"N","value_label":"None"},{"metric":"SI","name":"Integrity (Subsequent System)","value":"N","value_label":"None"},{"metric":"SA","name":"Availability (Subsequent System)","value":"N","value_label":"None"}]},"affected":[{"vendor_slug":"vanhauser-thc","vendor_name":"vanhauser-thc","product_slug":"thc-hydra","product_name":"thc-hydra","version_start":"0","version_start_inclusive":true,"version_end":"9.7","version_end_inclusive":true,"cpe23_uri":"cve5:vanhauser-thc:thc-hydra:0:9.7"},{"vendor_slug":"vanhauser-thc","vendor_name":"vanhauser-thc","product_slug":"thc-hydra","product_name":"thc-hydra","version_start":"9cc84c20e75f5fef6bb1790bb9ada2afad2204e2","version_start_inclusive":true,"version_end":"9cc84c20e75f5fef6bb1790bb9ada2afad2204e2","version_end_inclusive":true,"cpe23_uri":"cve5:vanhauser-thc:thc-hydra:9cc84c20e75f5fef6bb1790bb9ada2afad2204e2:9cc84c20e75f5fef6bb1790bb9ada2afad2204e2"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/vanhauser-thc/thc-hydra/commit/9cc84c20e75f5fef6bb1790bb9ada2afad2204e2","source_type":"PATCH","tags":["patch"]},{"url":"https://www.vulncheck.com/advisories/hydra-stack-buffer-overflow-in-ntlm-authentication-handler","source_type":"VENDOR_ADVISORY","tags":["advisory"]}],"timeline":[{"type":"published","at":"2026-06-25T18:01:07.362000Z","label":"CVE published","source":null}]}