{"id":"UBUNTU-CVE-2026-55200","details":"libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send crafted SSH packets with excessively large packet_length values to corrupt heap memory and achieve remote code execution.","modified":"2026-07-01T23:40:17.819666972Z","published":"2026-06-17T20:17:00Z","related":["USN-8486-1"],"upstream":["CVE-2026-55200"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-55200"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-55200"},{"type":"REPORT","url":"https://github.com/libssh2/libssh2/pull/2052"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8486-1"}],"affected":[{"package":{"name":"libssh2","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.11.1-1ubuntu0.25.10.2"}]}],"versions":["1.11.1-1","1.11.1-1build1","1.11.1-1ubuntu0.25.10.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libssh2-1t64","binary_version":"1.11.1-1ubuntu0.25.10.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55200.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.11.1-1ubuntu0.26.04.2"}]}],"versions":["1.11.1-1build1","1.11.1-1build2","1.11.1-1ubuntu0.26.04.1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"libssh2-1t64","binary_version":"1.11.1-1ubuntu0.26.04.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55200.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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:L"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}