{"id":"UBUNTU-CVE-2026-58051","details":"libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries before parsing populates them, so a parse failure reaching the cleanup path leaves libssh2_publickey_list_free operating on an uninitialized entry. A malicious SSH server offering the publickey subsystem can use a malformed response to make cleanup free an uninitialized, attacker-influenceable attrs pointer in a connecting libssh2 client.","modified":"2026-09-23T07:41:35.783296482Z","published":"2026-06-28T02:16:00Z","related":["USN-8532-1","USN-8799-1"],"upstream":["CVE-2026-58051"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-58051"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-58051"},{"type":"REPORT","url":"https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc"},{"type":"REPORT","url":"https://github.com/libssh2/libssh2/blob/master/src/publickey.c"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup"},{"type":"REPORT","url":"https://github.com/libssh2/libssh2/pull/2202"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8532-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8799-1"}],"affected":[{"package":{"name":"libssh2","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.3-2ubuntu0.2+esm4"}]}],"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","1.4.3-2ubuntu0.2+esm2","1.4.3-2ubuntu0.2+esm3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.4.3-2ubuntu0.2+esm4","binary_name":"libssh2-1"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58051.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=esm-apps-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5.0-2ubuntu0.1+esm3"}]}],"versions":["1.5.0-2","1.5.0-2ubuntu0.1","1.5.0-2ubuntu0.1+esm1","1.5.0-2ubuntu0.1+esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.5.0-2ubuntu0.1+esm3","binary_name":"libssh2-1"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58051.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.0-1ubuntu0.1+esm1"}]}],"versions":["1.8.0-1","1.8.0-1ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libssh2-1","binary_version":"1.8.0-1ubuntu0.1+esm1"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58051.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.0-2.1ubuntu0.1+esm1"}]}],"versions":["1.8.0-2.1build1","1.8.0-2.1ubuntu0.1"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"libssh2-1","binary_version":"1.8.0-2.1ubuntu0.1+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58051.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.10.0-3ubuntu0.1"}]}],"versions":["1.9.0-3","1.10.0-2","1.10.0-2build1","1.10.0-3"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"1.10.0-3ubuntu0.1","binary_name":"libssh2-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58051.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.11.0-4.1ubuntu0.24.04.3"}]}],"versions":["1.11.0-2","1.11.0-3","1.11.0-4","1.11.0-4.1build1","1.11.0-4.1build2","1.11.0-4.1ubuntu0.24.04.1","1.11.0-4.1ubuntu0.24.04.2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.11.0-4.1ubuntu0.24.04.3","binary_name":"libssh2-1t64"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58051.json"}},{"package":{"name":"libssh2","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/libssh2?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.11.1-1","1.11.1-1build1","1.11.1-1ubuntu0.25.10.1","1.11.1-1ubuntu0.25.10.2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.11.1-1ubuntu0.25.10.2","binary_name":"libssh2-1t64"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58051.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":"1.11.1-1ubuntu0.26.04.3"}]}],"versions":["1.11.1-1build1","1.11.1-1build2","1.11.1-1ubuntu0.26.04.1","1.11.1-1ubuntu0.26.04.2"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"libssh2-1t64","binary_version":"1.11.1-1ubuntu0.26.04.3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-58051.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}