Hydra Stack Buffer Overflow (CVE‑2026‑56766) Enables Remote Crash of Hydra ≤ 9.7
What Happened – A remote stack buffer overflow was disclosed in THC‑Hydra 9.5‑9.7 (CVE‑2026‑56766). An attacker can send a maliciously‑crafted NTLM Type‑2 challenge (e.g., an over‑long domain field) to trigger a SIGSEGV in Hydra’s NTLM authentication handler, causing the process to abort. The vulnerability is rated CVSS 7.5 (High) and has a public proof‑of‑concept exploit.
Why It Matters for Compliance & Audit Readiness –
- The flaw illustrates why continuous vulnerability‑management controls (e.g., automated scanning, patch tracking, and evidence of remediation) are a core SOC 2 requirement.
- Demonstrating timely remediation and documented patch‑deployment provides audit‑ready evidence for the CC6.1 – System Operations and CC7.2 – Change Management criteria.
Who Is Affected – Penetration‑testing teams, red‑team services, security‑consulting firms, and any organization that runs Hydra in production or as part of internal credential‑testing pipelines (across finance, tech, healthcare, etc.).
Recommended Actions –
- Verify Hydra version; upgrade to the patched commit (≥ 9.8) or apply the vendor’s patch.
- Add Hydra to your asset inventory and include it in automated vulnerability‑scanning baselines.
- Document the remediation step in your change‑management system and retain the patch‑commit hash as audit evidence.
Technical Notes – The exploit targets the NTLM authentication module (SMTP, POP3, IMAP, etc.) by delivering a 400‑byte domain field that overruns the stack. No CVE‑specific network service is required beyond Hydra’s client‑side execution. Source: Exploit‑DB 52622