If you run PHP in cgi-mode you are probably vulnerable to a newly found bug:
Heise: Gefahr-durch-offene-PHP-Luecke
Adding parameters like http://localhost/index.php?-s to an url can show the source code or even inject or run parametes in the shell.
Until an update exists it might be wise to filter out some string-elements (like “-” without “=”)
RewriteCond %{QUERY_STRING} ^(%2d|-)[^=]+$ [NC]
RewriteRule ^(.*) $1? [L]
Tags: exploits