Hydra – Stack Buffer Overflow in NTLM Authentication Handler_CVE-2026-56766

{
    "lastseen": "",
    "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": "2026-06-25T18:01:07.362Z",
    "modified": "2026-06-25T18:01:07.362Z",
    "type": "cve",
    "title": "Hydra - Stack Buffer Overflow in NTLM Authentication Handler",
    "source": "VulnCheck",
    "references": "https://github.com/vanhauser-thc/thc-hydra/commit/9cc84c20e75f5fef6bb1790bb9ada2afad2204e2\nhttps://www.vulncheck.com/advisories/hydra-stack-buffer-overflow-in-ntlm-authentication-handler",
    "id": "CVE-2026-56766",
    "bulletinFamily": "",
    "cwe": [
        "CWE-121"
    ],
    "cvelist": null,
    "sourceData": "vanhauser-thc thc-hydra 0",
    "sourceHref": "",
    "cvss": {
        "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",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "thc-hydra",
    "version": "0",
    "vendor": "vanhauser-thc",
    "ai_description": "Stack buffer overflow in NTLM authentication handler, enabling remote code execution",
    "ai_severity": "High",
    "ai_vendor": "vanhauser-thc",
    "ai_product": "thc-hydra",
    "ai_version": "through 9.7",
    "ai_score": 8.6
}