The remote web server uses a version of PHP that is affected by a remote code execution vulnerability.
According to its banner, the version of PHP installed on the remote host is earlier than 5.3.12 / 5.4.2, and as such is potentially affected by a remote code execution and information disclosure vulnerability. An error in the file 'sapi/cgi/cgi_main.c' can allow a remote attacker to obtain PHP source code from the web server or to potentially execute arbitrary code. In vulnerable configurations, PHP treats certain query string parameters as command line arguments including switches such as '-s', '-d', and '-c'. Note that this vulnerability is exploitable only when PHP is used in CGI-based configurations. Apache with 'mod_php' is not an exploitable configuration.
Upgrade to PHP version 5.3.12 / 5.4.2 or later. A 'mod_rewrite' workaround is available as well.