NTP before 4.2.8p9 rate limits responses received from the configured sources when rate limiting for all associations is enabled, which allows remote attackers to cause a denial of service (prevent responses from the sources) by sending responses with a spoofed source address.
http://nwtime.org/ntp428p9_release/
http://rhn.redhat.com/errata/RHSA-2017-0252.html
http://support.ntp.org/bin/view/Main/NtpBug3071
http://support.ntp.org/bin/view/Main/SecurityNotice#Recent_Vulnerabilities
http://www.securityfocus.com/bid/94451
http://www.securitytracker.com/id/1037354
https://bto.bluecoat.com/security-advisory/sa139
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03706en_us
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:39.ntp.asc
Source: MITRE
Published: 2017-01-13
Updated: 2020-06-18
Type: CWE-400
Base Score: 4.3
Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH