{"id":"UBUNTU-CVE-2026-2859","details":"Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows unauthenticated users to enumerate existing hosts by observing different HTTP response codes in deploy_agent endpoint, which could lead to information disclosure.","modified":"2026-03-20T08:07:22.922784Z","published":"2026-03-13T19:54:00Z","upstream":["CVE-2026-2859"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-2859"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-2859"},{"type":"REPORT","url":"https://checkmk.com/werk/18994"}],"affected":[{"package":{"name":"check-mk","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/check-mk@1.2.6p12-1ubuntu0.16.04.1+esm1?arch=source&distro=esm-apps/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.6p5-1","1.2.6p12-1","1.2.6p12-1ubuntu0.16.04.1","1.2.6p12-1ubuntu0.16.04.1+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"check-mk-agent","binary_version":"1.2.6p12-1ubuntu0.16.04.1+esm1"},{"binary_name":"check-mk-agent-logwatch","binary_version":"1.2.6p12-1ubuntu0.16.04.1+esm1"},{"binary_name":"check-mk-config-icinga","binary_version":"1.2.6p12-1ubuntu0.16.04.1+esm1"},{"binary_version":"1.2.6p12-1ubuntu0.16.04.1+esm1","binary_name":"check-mk-config-nagios3"},{"binary_name":"check-mk-livestatus","binary_version":"1.2.6p12-1ubuntu0.16.04.1+esm1"},{"binary_name":"check-mk-multisite","binary_version":"1.2.6p12-1ubuntu0.16.04.1+esm1"},{"binary_name":"check-mk-server","binary_version":"1.2.6p12-1ubuntu0.16.04.1+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-2859.json"}},{"package":{"name":"check-mk","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/check-mk@1.2.8p16-1ubuntu0.2?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8p16-1ubuntu0.1","1.2.8p16-1ubuntu0.2"],"ecosystem_specific":{"binaries":[{"binary_name":"check-mk-agent","binary_version":"1.2.8p16-1ubuntu0.2"},{"binary_version":"1.2.8p16-1ubuntu0.2","binary_name":"check-mk-agent-logwatch"},{"binary_name":"check-mk-config-icinga","binary_version":"1.2.8p16-1ubuntu0.2"},{"binary_name":"check-mk-livestatus","binary_version":"1.2.8p16-1ubuntu0.2"},{"binary_name":"check-mk-multisite","binary_version":"1.2.8p16-1ubuntu0.2"},{"binary_name":"check-mk-server","binary_version":"1.2.8p16-1ubuntu0.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-2859.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"},{"type":"Ubuntu","score":"medium"}]}