In ProFTPD through 1.3.8b before cec01cc, supplemental group inheritance grants unintended access to GID 0 because of the lack of supplemental groups from mod_sql.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:HI:NA:N7.5/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N