CVE-2021-22212

ntpkeygen can generate keys that ntpd fails to parse. NTPsec 1.2.0 allows
ntpkeygen to generate keys with ‘#’ characters. ntpd then either pads,
shortens the key, or fails to load these keys entirely, depending on the
key type and the placement of the ‘#’. This results in the administrator
not being able to use the keys as expected or the keys are shorter than
expected and easier to brute-force, possibly resulting in MITM attacks
between ntp clients and ntp servers. For short AES128 keys, ntpd generates
a warning that it is padding them.