Allure theme security problem- help needed

[DCE2007]

Hi,
I have been using the Allure theme for a while now. I have recently put a security site scanner in place to scan my website for security issues. It found issues with the Allure theme. I have added the information below. Please if you would advise on what to do to correct this situation.

Thanks,
D'

Question Dispute Resolve Port: http (80/tcp)
Status:
Not yet addressed

Synopsis:
The remote web server is prone to cross-site scripting attacks.
Description:
The remote web server hosts cgi scripts that fail to adequately sanitize
request strings with malicious JavaScript. By leveraging this issue,
an attacker may be able to cause arbitrary HTML and script code
to be executed in a user's browser within the security context of the
affected site.
These XSS are likely to be 'non persistent' or 'reflected'.

See Also:
http://en.wikipedia.org/wiki/Cross_s...Non-persistent http://jeremiahgrossman.blogspot.com...-pointing.html http://projects.webappsec.org/Cross-Site+Scripting

Risk Factor:
Medium / CVSS Base Score : 4.3(CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N)

Solution:Restrict access to the vulnerable application. Contact the vendor
for a patch or upgrade.


Output:
Using the GET HTTP method, Site Scanner found that :
+ The following resources may be vulnerable to cross-site scripting (quick test) :
/blog/wp-content/themes/allure_20/tools/timthumb.php?src=<script>alert(4
2);</script>
-------- output --------
file not found <script>alert(42);</script>