{"id":"UBUNTU-CVE-2026-56766","details":"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.","modified":"2026-06-29T23:19:15.192995452Z","published":"2026-06-25T19:16:00Z","upstream":["CVE-2026-56766"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-56766"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-56766"}],"affected":[{"package":{"name":"hydra","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/hydra?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.1-1","8.1-1build1","8.1-1build2"],"ecosystem_specific":{"binaries":[{"binary_name":"hydra","binary_version":"8.1-1build2"},{"binary_version":"8.1-1build2","binary_name":"hydra-gtk"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56766.json"}},{"package":{"name":"hydra","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/hydra?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["8.6-1","8.6-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"hydra","binary_version":"8.6-1build1"},{"binary_version":"8.6-1build1","binary_name":"hydra-gtk"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56766.json"}},{"package":{"name":"hydra","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/hydra?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.0-1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"9.0-1build1","binary_name":"hydra"},{"binary_name":"hydra-gtk","binary_version":"9.0-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56766.json"}},{"package":{"name":"hydra","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/hydra?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.1-1","9.2-1","9.2-1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"hydra","binary_version":"9.2-1ubuntu1"},{"binary_name":"hydra-gtk","binary_version":"9.2-1ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56766.json"}},{"package":{"name":"hydra","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/hydra?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.5-1","9.5-1build1","9.5-1build3"],"ecosystem_specific":{"binaries":[{"binary_version":"9.5-1build3","binary_name":"hydra"},{"binary_version":"9.5-1build3","binary_name":"hydra-gtk"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56766.json"}},{"package":{"name":"hydra","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/hydra?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.5-3build1"],"ecosystem_specific":{"binaries":[{"binary_name":"hydra","binary_version":"9.5-3build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56766.json"}},{"package":{"name":"hydra","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/hydra?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.5-3build1","9.6-3"],"ecosystem_specific":{"binaries":[{"binary_version":"9.6-3","binary_name":"hydra"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56766.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}