{"id":"UBUNTU-CVE-2019-3856","details":"An integer overflow flaw, which could lead to an out of bounds write, was discovered in libssh2 before 1.8.1 in the way keyboard prompt requests are parsed. A remote attacker who compromises a SSH server may be able to execute code on the client system when a user connects to the server.","modified":"2026-04-22T13:46:59.135843Z","published":"2019-03-25T19:29:00Z","related":["USN-5308-1"],"upstream":["CVE-2019-3856"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2019-3856"},{"type":"REPORT","url":"https://www.libssh2.org/CVE-2019-3856.html"},{"type":"REPORT","url":"https://github.com/libssh2/libssh2/pull/315"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5308-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2019-3856"}],"affected":[{"package":{"name":"libssh2","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/libssh2@1.4.3-2ubuntu0.2+esm2?arch=source&distro=trusty/esm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.3-2ubuntu0.2+esm2"}]}],"versions":["1.4.3-1","1.4.3-2","1.4.3-2ubuntu0.1","1.4.3-2ubuntu0.2","1.4.3-2ubuntu0.2+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libssh2-1","binary_version":"1.4.3-2ubuntu0.2+esm2"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2019/UBUNTU-CVE-2019-3856.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/libssh2@1.5.0-2ubuntu0.1+esm1?arch=source&distro=esm-apps/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5.0-2ubuntu0.1+esm1"}]}],"versions":["1.5.0-2","1.5.0-2ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libssh2-1","binary_version":"1.5.0-2ubuntu0.1+esm1"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2019/UBUNTU-CVE-2019-3856.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/libssh2@1.8.0-1ubuntu0.1?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.8.0-1","1.8.0-1ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libssh2-1","binary_version":"1.8.0-1ubuntu0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2019/UBUNTU-CVE-2019-3856.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}