{"id":"GHSA-v83q-83hj-rw38","aliases":[],"status":"published","title":"ntpd NTS client denial of service via wrongly sized cookies","description":"Two denial of service vulnerabilities were found in ntpd-rs related to the handling of NTS cookies in our client functionality. Whenever an NTS source is configured and the server behind that source is sending zero-sized cookies or cookies larger than what would fit in our buffer size, ntpd-rs would crash. Only configured NTS sources can abuse these vulnerabilities. NTP sources or third parties that are not configured cannot make use of these vulnerabilities.\n\nFor zero-sized cookies: a division by zero would force an exit when the number of new cookies that would need to be requested is calculated. In ntpd-rs 1.5.0 a check was added to prevent the division by zero.\n\nFor large cookies: while trying to send a NTP request with the cookie included, the buffer is too small to handle the cookie and an exit of ntpd-rs is forced once a write to the buffer is attempted. The memory outside the buffer would not be written to in this case. In ntpd-rs 1.5.0 a check was added that prevents accepting cookies larger than 350 bytes.\n\nUsers of older versions of ntpd-rs are recommended to update to the latest version. If an update is impossible, it is recommended to only add NTS sources to ntpd-rs that are trusted to not abuse this bug.","severity":{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium","from":"ghsa"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-369","CWE-703"],"published":"2025-02-28T17:46:36Z","modified":"2025-03-15T20:37:11Z","fixes":[{"ecosystem":"crates.io","package":"ntpd","fixed_in":["1.5.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"ntpd","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.5.0"}]}]},{"source":"osv","ecosystem":"crates.io","package":"ntpd","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.5.0"}]}]}],"references":[{"url":"https://github.com/pendulum-project/ntpd-rs/security/advisories/GHSA-v83q-83hj-rw38","tags":["web"]},{"url":"https://github.com/pendulum-project/ntpd-rs/commit/10a103b471dae25ac598140df0c195b6531bf716","tags":["web"]},{"url":"https://github.com/pendulum-project/ntpd-rs/commit/37dd8d9a0faa03e7dfe3a4bf64953010f075c3e2","tags":["web"]},{"url":"https://github.com/advisories/GHSA-v83q-83hj-rw38"},{"url":"https://github.com/pendulum-project/ntpd-rs","tags":["package"]}],"sources":{"ghsa":[{"id":"GHSA-v83q-83hj-rw38","title":"ntpd NTS client denial of service via wrongly sized cookies","description":"Two denial of service vulnerabilities were found in ntpd-rs related to the handling of NTS cookies in our client functionality. Whenever an NTS source is configured and the server behind that source is sending zero-sized cookies or cookies larger than what would fit in our buffer size, ntpd-rs would crash. Only configured NTS sources can abuse these vulnerabilities. NTP sources or third parties that are not configured cannot make use of these vulnerabilities.\n\nFor zero-sized cookies: a division by zero would force an exit when the number of new cookies that would need to be requested is calculated. In ntpd-rs 1.5.0 a check was added to prevent the division by zero.\n\nFor large cookies: while trying to send a NTP request with the cookie included, the buffer is too small to handle the cookie and an exit of ntpd-rs is forced once a write to the buffer is attempted. The memory outside the buffer would not be written to in this case. In ntpd-rs 1.5.0 a check was added that prevents accepting cookies larger than 350 bytes.\n\nUsers of older versions of ntpd-rs are recommended to update to the latest version. If an update is impossible, it is recommended to only add NTS sources to ntpd-rs that are trusted to not abuse this bug.","status":"published","published":"2025-02-28T17:46:36Z","modified":"2025-03-15T20:37:11Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-369","CWE-703"],"updated_at":"2026-11-02T14:38:34.992855Z"}],"osv":[{"id":"GHSA-v83q-83hj-rw38","title":"ntpd NTS client denial of service via wrongly sized cookies","description":"Two denial of service vulnerabilities were found in ntpd-rs related to the handling of NTS cookies in our client functionality. Whenever an NTS source is configured and the server behind that source is sending zero-sized cookies or cookies larger than what would fit in our buffer size, ntpd-rs would crash. Only configured NTS sources can abuse these vulnerabilities. NTP sources or third parties that are not configured cannot make use of these vulnerabilities.\n\nFor zero-sized cookies: a division by zero would force an exit when the number of new cookies that would need to be requested is calculated. In ntpd-rs 1.5.0 a check was added to prevent the division by zero.\n\nFor large cookies: while trying to send a NTP request with the cookie included, the buffer is too small to handle the cookie and an exit of ntpd-rs is forced once a write to the buffer is attempted. The memory outside the buffer would not be written to in this case. In ntpd-rs 1.5.0 a check was added that prevents accepting cookies larger than 350 bytes.\n\nUsers of older versions of ntpd-rs are recommended to update to the latest version. If an update is impossible, it is recommended to only add NTS sources to ntpd-rs that are trusted to not abuse this bug.","status":"published","published":"2025-02-28T17:46:36Z","modified":"2025-02-28T17:46:36Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-369","CWE-703"],"updated_at":"2026-11-02T15:46:56.981655Z"}]}}