CVE-2026-56766
HIGH
MEDIUM
Priority: 0.21
BB Relevance:
68/100
Published: 2026-06-25
Modified: 2026-10-25
First seen: 2026-10-29
Status: active
Attack Surface
Network
Low Complexity
No Auth
Conf. Impact
Integ. Impact
CVSS Vector Breakdown
AV:
Network
AC:
Low
PR:
None
UI:
Active
S:
X
AT:
None
VC:
High
VI:
High
VA:
High
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.