The following code exhibits the trouble. 
#!/usr/bin/perl -wT
use strict
my $tainteddata = $ARGV[0];
my ($untainteddata) = $tainteddata =~ /^([\w]+)$/;
open(my $fh, ">", $untainteddata) or die;
printf $fh <<EOMEOM;
removing the next line of output allows the script to work
the tainted data: $tainteddata
script works with or without the following line
the untainted data: $untainteddata
EOMEOM
close ($fh);
exit;

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In trying other solutions, I've determined that the here document appears to be the culprit. The following code works fine. 
#!/usr/bin/perl -wT
use strict;
my $tainteddata = $ARGV[0];
my ($untainteddata) = $tainteddata =~ /^([\w]+)$/;
open(my $fh, ">", $untainteddata) or die;
printf $fh $tainteddata, "\n";
close ($fh);
exit;

[download]
This is curious to me. Why the different behavior for here documents? Original version of perl was 5.8.9, now 5.10.1.

In reply to Re^2: Taint, CGI and perl 5.10 by nextguru
in thread Taint, CGI and perl 5.10 by nextguru

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