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TI-2026-40930 Aliases CVE-2026-56766GHSA-3r6x-6cp5-6575

Hydra - Stack Buffer Overflow in NTLM Authentication Handler

Priority MEDIUM 44CWE-121Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Active
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-121 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.02438 84th percentileScored 2026-11-07
Fix Fixed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
vanhauser-thcthc-hydraup to 9.7—Patch availableCNA
  • thc-hydra Vendorvanhauser-thc Affected up to 9.7 Fixed in — Patch available CNA

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-56766
  2. 2026-10-03 Alias added: GHSA-3r6x-6cp5-6575

References

Patch 1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences