XMB contains a flaw that may lead to an unauthorized information disclosure. The issue is triggered when a remote attacker provides malformed input to the 'fid' variable of the post.php script, which will disclose the software's installation path resulting in a loss of confidentiality. While such information is relatively low risk, it is often useful in carrying out additional, more focused attacks.
Upgrade to version 1.9.8 SP2 or higher, as it has been reported to fix this vulnerability. An upgrade is required as there are no known workarounds.