{"id":"CVE-2026-56766","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-56766","generatedAt":"2026-10-28T04:46:21.230Z","title":"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.","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":"2026-06-25T19:16:44.000Z","lastModified":"2026-10-25T22:10:00.000Z","status":"Deferred","sourceIdentifier":"disclosure@vulncheck.com","cvss":{"version":"4.0","score":8.6,"severity":"HIGH","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-121"],"affected":[],"epss":{"score":0.02438,"percentile":0.84205,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":1,"verified":false,"firstPublished":"2026-07-07","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":52622,"kind":"exploit","title":"Hydra - Stack Buffer Overflow","url":"https://www.exploit-db.com/exploits/52622","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/linux/remote/52622.py","file":"exploits/linux/remote/52622.py","published":"2026-07-07","added":"2026-07-07","updated":"2026-07-07","author":"banyamer","type":"remote","platform":"linux","port":null,"verified":false,"codes":["CVE-2026-56766"],"tags":null,"aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":null}]},"verdict":{"level":"urgent","text":"A public exploit is published in Exploit-DB and the impact is high, while EPSS rates exploitation at 2.4%. Anyone can run this; patch or mitigate before the next change window and check exposed instances for signs of use."},"changes":[],"references":[{"url":"https://github.com/vanhauser-thc/thc-hydra/commit/9cc84c20e75f5fef6bb1790bb9ada2afad2204e2","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/hydra-stack-buffer-overflow-in-ntlm-authentication-handler","source":"disclosure@vulncheck.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-56766","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}