CVE-2026-56766
Hydra - Stack Buffer Overflow in NTLM Authentication Handler
- State
- Published
- Severity
- 8.6 High
- Published
- Jun 25, 2026
- Updated
- Jul 14, 2026
- Reserved
- Jun 22, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.6 High | 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 | VulnCheck |
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-121 Stack-based Buffer Overflow
Affected Products
| Product | Versions |
|---|---|
thc-hydravanhauser-thc |
|
References
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