And from the HTML::Entities documentation:
If called in void context the arguments are decoded in-place.
So the solution is to not call in void context: 
$filename = decode_entities($filename);

[download]
As a side note, if you are migrating or securing an old script, you should take a read through perltaint. It'll help you protect yourself from classic exploits.

#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

In reply to Re^2: CGI Filenames and decode_entities by kennethk
in thread CGI Filenames and decode_entities by Marais

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