{"id":"USN-8872-1","summary":"libxmltok vulnerabilities","details":"It was discovered that Expat, contained with the xmltok library did not\ncorrectly handle certain integer arithmetic. If a user or automated\nsystem were tricked into opening a specially crafted file, an attacker\ncould possibly cause a denial of service. (CVE-2026-56404, CVE-2026-56405)","modified":"2026-10-06T10:57:50.476314159Z","published":"2026-10-05T23:54:25Z","related":["UBUNTU-CVE-2026-56404","UBUNTU-CVE-2026-56405"],"upstream":["CVE-2026-56404","CVE-2026-56405","UBUNTU-CVE-2026-56404","UBUNTU-CVE-2026-56405"],"references":[{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8872-1"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-56404"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-56405"}],"affected":[{"package":{"name":"libxmltok","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/libxmltok?arch=source&distro=esm-apps-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2-3ubuntu0.1~esm1"}]}],"versions":["1.2-3build3"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro","binaries":[{"binary_name":"libxmltok1","binary_version":"1.2-3ubuntu0.1~esm1"}]},"database_specific":{"cves_map":{"ecosystem":"Ubuntu:Pro:16.04:LTS","cves":[{"id":"CVE-2026-56404","severity":[{"score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","type":"CVSS_V3"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"score":"medium","type":"Ubuntu"}]},{"id":"CVE-2026-56405","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"Ubuntu","score":"medium"}]}]},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8872-1.json"}},{"package":{"name":"libxmltok","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/libxmltok?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2-4ubuntu0.18.04.1~esm7"}]}],"versions":["1.2-4","1.2-4ubuntu0.18.04.1~esm1","1.2-4ubuntu0.18.04.1~esm2","1.2-4ubuntu0.18.04.1~esm3","1.2-4ubuntu0.18.04.1~esm4","1.2-4ubuntu0.18.04.1~esm5","1.2-4ubuntu0.18.04.1~esm6"],"ecosystem_specific":{"binaries":[{"binary_name":"libxmltok1","binary_version":"1.2-4ubuntu0.18.04.1~esm7"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"cves_map":{"ecosystem":"Ubuntu:Pro:18.04:LTS","cves":[{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-56404"},{"id":"CVE-2026-56405","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"Ubuntu","score":"medium"}]}]},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8872-1.json"}},{"package":{"name":"libxmltok","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/libxmltok?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2-4ubuntu0.20.04.1~esm7"}]}],"versions":["1.2-4","1.2-4ubuntu0.20.04.1~esm1","1.2-4ubuntu0.20.04.1~esm2","1.2-4ubuntu0.20.04.1~esm3","1.2-4ubuntu0.20.04.1~esm4","1.2-4ubuntu0.20.04.1~esm5","1.2-4ubuntu0.20.04.1~esm6"],"ecosystem_specific":{"binaries":[{"binary_name":"libxmltok1","binary_version":"1.2-4ubuntu0.20.04.1~esm7"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8872-1.json","cves_map":{"cves":[{"id":"CVE-2026-56404","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","type":"CVSS_V3"},{"score":"medium","type":"Ubuntu"}]},{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","type":"CVSS_V3"},{"score":"medium","type":"Ubuntu"}],"id":"CVE-2026-56405"}],"ecosystem":"Ubuntu:Pro:20.04:LTS"}}},{"package":{"name":"libxmltok","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/libxmltok?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2-4ubuntu0.22.04.1~esm7"}]}],"versions":["1.2-4","1.2-4ubuntu0.22.04.1~esm1","1.2-4ubuntu0.22.04.1~esm2","1.2-4ubuntu0.22.04.1~esm3","1.2-4ubuntu0.22.04.1~esm4","1.2-4ubuntu0.22.04.1~esm5","1.2-4ubuntu0.22.04.1~esm6"],"ecosystem_specific":{"binaries":[{"binary_name":"libxmltok1","binary_version":"1.2-4ubuntu0.22.04.1~esm7"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"cves_map":{"ecosystem":"Ubuntu:Pro:22.04:LTS","cves":[{"severity":[{"score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","type":"CVSS_V3"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-56404"},{"id":"CVE-2026-56405","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"Ubuntu","score":"medium"}]}]},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8872-1.json"}},{"package":{"name":"libxmltok","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/libxmltok?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2-4.1ubuntu2.24.0.4.1+esm5"}]}],"versions":["1.2-4ubuntu1","1.2-4.1ubuntu1","1.2-4.1ubuntu2","1.2-4.1ubuntu2.24.0.4.1+esm1","1.2-4.1ubuntu2.24.0.4.1+esm2","1.2-4.1ubuntu2.24.0.4.1+esm3","1.2-4.1ubuntu2.24.0.4.1+esm4"],"ecosystem_specific":{"binaries":[{"binary_name":"libxmltok1t64","binary_version":"1.2-4.1ubuntu2.24.0.4.1+esm5"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"cves_map":{"ecosystem":"Ubuntu:Pro:24.04:LTS","cves":[{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","type":"CVSS_V3"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-56404"},{"severity":[{"score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","type":"CVSS_V3"},{"score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","type":"CVSS_V3"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-56405"}]},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8872-1.json"}}],"schema_version":"1.9.0"}