Is CVE-2026-56766 actively exploited?

No active exploitation of CVE-2026-56766 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-56766 be exploited remotely?

Yes. CVE-2026-56766 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-56766?

CVE-2026-56766 has a CVSS score of 8.8 (HIGH).

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HIGH

CVE-2026-56766

CWE-121Published: June 25, 2026· Updated: Jun 25, 2026

8.8

CVSS v3.1

EPSS:0.47%probability of exploitation in 30 daysPercentile:37.4th

Official 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.

NVD Source

Technical Analysis

CVE-2026-56766 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.