In GIMP 2.8.22, there is a heap-based buffer overflow in the fli_read_brun function in plug-ins/file-fli/fli.c.
https://www.debian.org/security/2017/dsa-4077
https://usn.ubuntu.com/3539-1/
https://lists.debian.org/debian-lts-announce/2017/12/msg00023.html