To replicate on a vanilla liferay:

1. Login as the 'test@liferay.com' user, and add a 'Wiki Display' portlet (and a 'Wiki' portlet so you have at least 1 page to choose from) to the guest page.
2. In the 'Wiki Display' portlet, click the 'Please configure this portlet to make it visible to all users' link.
3. From the 'node' dropdown, choose 'Main' and click 'Save'.
4. Close the dialog, and in the wiki display portlet click the 'This page is empty. Edit it to add some text' link.
5. Click on the 'Attachments' tab, then 'Add Attachments'.
6. Click the green 'Browse' bar, and choose any file to upload.
7. On trying to upload, you will get "Invalid authentication token" in console.

Reproduce on trunk rev. 111409