{"id":"UBUNTU-CVE-2015-1853","details":"chrony before 1.31.1 does not properly protect state variables in authenticated symmetric NTP associations, which allows remote attackers with knowledge of NTP peering to cause a denial of service (inability to synchronize) via random timestamps in crafted NTP data packets.","modified":"2025-09-08T16:43:20Z","published":"2019-12-09T19:15:00Z","upstream":["CVE-2015-1853"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2015-1853"},{"type":"REPORT","url":"http://www.openwall.com/lists/oss-security/2015/04/07/10"},{"type":"REPORT","url":"http://chrony.tuxfamily.org/News.html"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2015-1853"}],"affected":[{"package":{"name":"chrony","ecosystem":"Ubuntu:14.04:LTS","purl":"pkg:deb/ubuntu/chrony@1.29-1ubuntu0.1?arch=source&distro=trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.29-1ubuntu0.1"}]}],"versions":["1.26-4","1.29-1"],"ecosystem_specific":{"binaries":[{"binary_name":"chrony","binary_version":"1.29-1ubuntu0.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2015/UBUNTU-CVE-2015-1853.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}