Enabling CORS on IIS for only Font files

Question

Is there a way to enable CORS for only files of a certain type on IIS7? I am going off this article (https://www.maxcdn.com/one/tutorial/how-to-use-cdn-with-webfonts/) and noticed that the Apache and nginx examples show that CORS is only enabled if the request is looking for a certain Content-Type, whereas the IIS example shows CORS enabled for everything.

I have CSS that is being referenced on an external site but the font files are being blocked by the browser and wish to enable CORS on IIS7 but only for .woff, .woff2, .tff, .eot, and .svg files. I do not wish to enable CORS for everything if possible.

Answer 1

Hackerman's answer is great and it led me to a solution, however, there are a few adjustments that I had to make. The first was placing the rule in the outboundRules section under the rewrite node.

<outboundRules>
    <rule name="Enable CORS for Fonts">
        <match serverVariable="RESPONSE_Access_Control_Allow_Origin" pattern=".*" />
        <conditions>
          <add input="{REQUEST_URI}" pattern="^[^\?]+\.(ttf|otf|eot|woff|woff2|svg)(\?.*)?$" />
        </conditions>
        <action type="Rewrite" value="*" />
    </rule>
</outboundRules>

Lastly, the regex was updated to prevent requests such as the one below, which would allow someone to request any URL across origins:

/some/critical/javascript/file.js?v=.woff
/api/secure/users?v=.woff

... but it still allows the following

/some/font.woff
/some/font.woff?etag
/some/font.woff?v=123