E.g. from ftview.c

static struct  status_
{
...
char           header_buffer[256];
...


in write_header( FT_Error  error_code )
{
...
sprintf( status.header_buffer, "File `%s': error 0x%04x",
                 basename, (FT_UShort)error_code );


with a long filename it produces on Linux with glibc

* buffer overflow detected *: /usr/local/fuzz/ttf/ftview terminated
======= Backtrace: =========
/lib/libc.so.6(__fortify_fail+0x37)[0x7ffff71011d7]
/lib/libc.so.6(+0xfe090)[0x7ffff7100090]
/lib/libc.so.6(+0xfd4f9)[0x7ffff70ff4f9]
/lib/libc.so.6(_IO_default_xsputn+0xcc)[0x7ffff7077d1c]
/lib/libc.so.6(_IO_vfprintf+0x3d34)[0x7ffff704b0d4]
/lib/libc.so.6(__vsprintf_chk+0x99)[0x7ffff70ff599]
/lib/libc.so.6(__sprintf_chk+0x7f)[0x7ffff70ff4df]
/usr/local/fuzz/ttf/ftview[0x404ba0]
/lib/libc.so.6(__libc_start_main+0xfd)[0x7ffff7020c4d]
/usr/local/fuzz/ttf/ftview[0x402849]


I recommend changing every sprintf into snprintf