Sure, I will. Guestbook is my current favourite... Check out this "ultra-leet" substitution: 
  s[
    (?: <!--.*?-->                                   ) |
    (?: <[?!].*?>                                    ) |
    (?: <([a-z0-9]+)\b((?:[^>'"]|"[^"]*"|'[^']*')*)> ) |
    (?: </([a-z0-9]+)>                               ) |
    (?: (.[^<]*)                                     )
  ][
    defined $1 ? cleanup_tag(lc $1, $2)              :
    defined $3 ? cleanup_close(lc $3)                :
    defined $4 ? cleanup_cdata($4)                   :
    ''
  ]igesx;

[download]
No comments to explain it. I understand it. If you'd asked me a year ago, I'd have had no clue. If the code is vanity code to prove how clever the authors are, that's GREAT. But, I don't believe that was their intention. Or at least, it's claimed it wasn't.

The particular bug that springs to mind was that you could wipe the entire guestbook from view using comment tags, and possibly invoke SSIs if they were enabled. I submitted a patch, and it was patched. Matt's code wasn't vulnerable to this.

In reply to Re: Re: CGI scripts and NMS by sheriff
in thread CGI scripts and NMS by busunsl

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