{"id":"USN-8093-1","summary":"libssh vulnerability","details":"It was discovered that libssh incorrectly performed bounds checking when\nprocessing SFTP extensions. If a client application queried extension data out\nof bounds, it could cause the application to crash, resulting in a denial of\nservice, or exhibit unintended behavior.","modified":"2026-05-20T16:06:17.938264065Z","published":"2026-03-16T10:57:11Z","related":["UBUNTU-CVE-2026-3731"],"upstream":["UBUNTU-CVE-2026-3731"],"references":[{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8093-1"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-3731"}],"affected":[{"package":{"name":"libssh","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/libssh?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.6.3-4.3ubuntu0.6+esm5"}]}],"versions":["0.6.3-3ubuntu3","0.6.3-4.1","0.6.3-4.2","0.6.3-4.2ubuntu1","0.6.3-4.3","0.6.3-4.3ubuntu0.1","0.6.3-4.3ubuntu0.2","0.6.3-4.3ubuntu0.5","0.6.3-4.3ubuntu0.6","0.6.3-4.3ubuntu0.6+esm1","0.6.3-4.3ubuntu0.6+esm2","0.6.3-4.3ubuntu0.6+esm3","0.6.3-4.3ubuntu0.6+esm4"],"ecosystem_specific":{"binaries":[{"binary_version":"0.6.3-4.3ubuntu0.6+esm5","binary_name":"libssh-4"},{"binary_version":"0.6.3-4.3ubuntu0.6+esm5","binary_name":"libssh-gcrypt-4"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8093-1.json","cves_map":{"cves":[],"ecosystem":"Ubuntu:Pro:16.04:LTS"}}},{"package":{"name":"libssh","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/libssh?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7"}]}],"versions":["0.7.5-1","0.8.0~20170825.94fa1e38-1","0.8.0~20170825.94fa1e38-1build1","0.8.0~20170825.94fa1e38-1ubuntu0.1","0.8.0~20170825.94fa1e38-1ubuntu0.2","0.8.0~20170825.94fa1e38-1ubuntu0.5","0.8.0~20170825.94fa1e38-1ubuntu0.6","0.8.0~20170825.94fa1e38-1ubuntu0.7","0.8.0~20170825.94fa1e38-1ubuntu0.7+esm3","0.8.0~20170825.94fa1e38-1ubuntu0.7+esm4","0.8.0~20170825.94fa1e38-1ubuntu0.7+esm5","0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6"],"ecosystem_specific":{"binaries":[{"binary_version":"0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7","binary_name":"libssh-4"},{"binary_version":"0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7","binary_name":"libssh-gcrypt-4"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8093-1.json","cves_map":{"cves":[{"id":"CVE-2026-3731","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}],"ecosystem":"Ubuntu:Pro:18.04:LTS"}}},{"package":{"name":"libssh","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/libssh?arch=source&distro=esm-infra%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.3-2ubuntu2.5+esm4"}]}],"versions":["0.9.0-1ubuntu1","0.9.0-1ubuntu4","0.9.0-1ubuntu5","0.9.3-2ubuntu1","0.9.3-2ubuntu2","0.9.3-2ubuntu2.1","0.9.3-2ubuntu2.2","0.9.3-2ubuntu2.3","0.9.3-2ubuntu2.4","0.9.3-2ubuntu2.5","0.9.3-2ubuntu2.5+esm1","0.9.3-2ubuntu2.5+esm2","0.9.3-2ubuntu2.5+esm3"],"ecosystem_specific":{"binaries":[{"binary_version":"0.9.3-2ubuntu2.5+esm4","binary_name":"libssh-4"},{"binary_version":"0.9.3-2ubuntu2.5+esm4","binary_name":"libssh-gcrypt-4"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8093-1.json","cves_map":{"cves":[{"id":"CVE-2026-3731","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}],"ecosystem":"Ubuntu:Pro:20.04:LTS"}}},{"package":{"name":"libssh","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libssh?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.6-2ubuntu0.22.04.7"}]}],"versions":["0.9.6-1","0.9.6-1build1","0.9.6-2","0.9.6-2build1","0.9.6-2ubuntu0.22.04.1","0.9.6-2ubuntu0.22.04.2","0.9.6-2ubuntu0.22.04.3","0.9.6-2ubuntu0.22.04.4","0.9.6-2ubuntu0.22.04.5","0.9.6-2ubuntu0.22.04.6"],"ecosystem_specific":{"binaries":[{"binary_version":"0.9.6-2ubuntu0.22.04.7","binary_name":"libssh-4"},{"binary_version":"0.9.6-2ubuntu0.22.04.7","binary_name":"libssh-gcrypt-4"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8093-1.json","cves_map":{"cves":[{"id":"CVE-2026-3731","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}],"ecosystem":"Ubuntu:22.04:LTS"}}},{"package":{"name":"libssh","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libssh?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.10.6-2ubuntu0.4"}]}],"versions":["0.10.5-3ubuntu1","0.10.5-3ubuntu2","0.10.6-2","0.10.6-2build1","0.10.6-2build2","0.10.6-2ubuntu0.1","0.10.6-2ubuntu0.2","0.10.6-2ubuntu0.3"],"ecosystem_specific":{"binaries":[{"binary_version":"0.10.6-2ubuntu0.4","binary_name":"libssh-4"},{"binary_version":"0.10.6-2ubuntu0.4","binary_name":"libssh-gcrypt-4"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8093-1.json","cves_map":{"cves":[{"id":"CVE-2026-3731","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}],"ecosystem":"Ubuntu:24.04:LTS"}}},{"package":{"name":"libssh","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/libssh?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.11.2-1ubuntu0.3"}]}],"versions":["0.11.1-1","0.11.1-2","0.11.2-1","0.11.2-1build1","0.11.2-1ubuntu0.1","0.11.2-1ubuntu0.2"],"ecosystem_specific":{"binaries":[{"binary_version":"0.11.2-1ubuntu0.3","binary_name":"libssh-4"}],"availability":"No subscription 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