[exim] Should the taint checks apply to arguments?

I understand why it is dangerous to use tainted data in constructing
filenames so I can no longer run a command containing the local_part,
e.g.

data = |/home/exim/scripts/$local_part

I see that it is also an error to use, e.g.

data = |/home/exim/scripts/my_script $local_part

In this case the script is fixed and the tainted data is being used as
an argument. Is that still dangerous? The script can pick up the
local_part from the LOCAL_PART environment variable.

Richard
--
Richard Gilbert
IT Services
University of Sheffield, Sheffield, S10 2FN, UK
Phone: +44 114 222 3028