The pnVarPrepForStore function in PostNuke 0.764 and earlier skips input sanitization when magic_quotes_runtime is enabled, which allows remote attackers to conduct SQL injection attacks and execute arbitrary SQL commands via input associated with server variables, as demonstrated by the CLIENT_IP HTTP header (HTTP_CLIENT_IP variable).

More... (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2008-1591)