Fcron 2.0.1, 2.9.4, and possibly earlier versions leak file descriptors of open files, which allows local users to bypass access restrictions and read fcron.allow and fcron.deny via the EDITOR environment variable.
Exploitability
AV:LAC:LAu:NImpact
C:PI:NA:N2.1/AV:L/AC:L/Au:N/C:P/I:N/A:N