Cross-site Scripting in Filter Stream Converter Application in XWiki Platform

Impact

We found a possible XSS vector in the Filter.FilterStreamDescriptorForm wiki page related to pretty much all the form fields printed in the home page of the application.

Patches

The issue is patched in versions 12.10.11, 14.0-rc-1, 13.4.7, 13.10.3.

Workarounds

The easiest workaround is to edit the wiki page Filter.FilterStreamDescriptorForm (with wiki editor) and change the lines

          <input type="text" id="$descriptorId" name="$descriptorId" value="#if($request.get($descriptorId))$request.get($descriptorId)#else$descriptor.defaultValue#end"/>
        #else
          <input type="text" id="$descriptorId" name="$descriptorId"#if($request.get($descriptorId))value="$request.get($descriptorId)"#end/>

into

          <input type="text" id="$descriptorId" name="$descriptorId" value="#if($request.get($descriptorId))$escapetool.xml($request.get($descriptorId))#else$descriptor.defaultValue#end"/>
        #else
          <input type="text" id="$descriptorId" name="$descriptorId"#if($request.get($descriptorId))value="$escapetool.xml($request.get($descriptorId))"#end/>