A stack buffer overflow in ntpq can be triggered by a malicious ntpd server when ntpq requests the restriction list from the server. This is due to a missing length check in the reslist() function. It occurs whenever the function parses the server's response and encounters a flagstr variable of an excessive length. The string will be copied into a fixed-size buffer, leading to an overflow on the function's stack-frame. Note well that this problem requires a malicious server, and affects ntpq, not ntpd.
Affects: All versions of ntpq, up to but not including ntp-4.2.8p10, and ntp-4.3.0 up to, but not including ntp-4.3.94.
Name: the NTP project
Created ntp tracking bugs for this issue:
Affects: fedora-all [bug 1435163]
This flaw affects the mode6 reslist command, which is not supported by ntp-4.2.6p5 or earlier in Red Hat Enterprise Linux or Fedora <= 25.