{"id":"CVE-2026-56766","state":"PUBLISHED","title":"Hydra - Stack Buffer Overflow in NTLM Authentication Handler","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.","publishedAt":"2026-06-25T18:01:07.362Z","updatedAt":"2026-07-14T21:34:18.775Z","severity":{"score":8.6,"label":"High","version":"4.0","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","source":"VulnCheck"},"assigner":"VulnCheck","products":["vanhauser-thc thc-hydra"],"affected":[{"vendor":"vanhauser-thc","product":"thc-hydra","packageURL":"pkg:github/vanhauser-thc/thc-hydra","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"9.7","versionType":"custom"},{"version":"9cc84c20e75f5fef6bb1790bb9ada2afad2204e2","status":"unaffected","versionType":"git"}],"repo":"https://github.com/vanhauser-thc/thc-hydra"}],"references":["https://github.com/vanhauser-thc/thc-hydra/commit/9cc84c20e75f5fef6bb1790bb9ada2afad2204e2","https://www.vulncheck.com/advisories/hydra-stack-buffer-overflow-in-ntlm-authentication-handler"],"weaknesses":["CWE-121"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/56xxx/CVE-2026-56766.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56766","state":"PUBLISHED","datePublished":"2026-06-25T18:01:07.362Z","dateUpdated":"2026-07-14T21:34:18.775Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-06-22T21:55:17.942Z"},"containers":{"cna":{"title":"Hydra - Stack Buffer Overflow in NTLM Authentication Handler","descriptions":[{"lang":"en","value":"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. 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