CVE-2026-56766
Buffer overflow in Hydra NTLM auth modules enables remote code execution.
Is CVE-2026-56766 being exploited?
Not confirmed. CVE-2026-56766 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 2.4% probability of exploitation in the next 30 days.
How severe is CVE-2026-56766?
CVE-2026-56766 is rated High with a CVSS score of 8.6. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-56766?
Yes. A fix has been recorded for CVE-2026-56766. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-56766 affect?
CVE-2026-56766 affects Hydra NTLM authentication modules (SMTP, POP3, IMAP, NNTP, HTTP, HTTP-Proxy, HTTP-Proxy-Urlenum). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-56766?
Upgrade to patched Hydra version; verify NTLM paths.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
RCE via crafted NTLM Type-2 challenge; 500-byte stack overflow on unprotected systems.
Patch when possible
- affected<= 9.7
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.