PT-2026-52540 · Vanhauser Thc · Thc-Hydra

Tristan Madani · Published 2026-06-25 · Updated 2026-06-25 · CVE-2026-56766

NVD

CVSS v3.1

8.8

High

Base vector

AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

Fix

Stack Overflow

Weakness Enumeration

CWE-121

Related Identifiers

CVE-2026-56766

Affected Products

Thc-Hydra

References · 3

• https://github.com/vanhauser-thc/thc-hydra/commit/9cc84c20e75f5fef6bb1790bb9ada2afad2204e2 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-56766 · Security Note
• https://vulncheck.com/advisories/hydra-stack-buffer-overflow-in-ntlm-authentication-handler · Note