Dancer2::Plugin::Auth::OAuth versions before 0.22 for Perl default to a predictable nonce.
The default nonce was generated using an MD5 hash of the epoch time, which is predictable.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:HI:HA:N9.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NOther