The tempname_ensure function in lib/routines.h in a2ps 4.14 and earlier, as used by the spy_user function and possibly other functions, allows local users to modify arbitrary files via a symlink attack on a temporary file.
https://bugzilla.redhat.com/show_bug.cgi?id=1060630
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=737385
http://www.debian.org/security/2014/dsa-2892
http://seclists.org/oss-sec/2014/q1/257
http://seclists.org/oss-sec/2014/q1/253
http://seclists.org/oss-sec/2014/q1/237
http://pkgs.fedoraproject.org/cgit/a2ps.git/plain/a2ps-4.13-security.patch