User content uploaded onto answers.atlassian.com is indexable by Google due to the lack of appropriate indexing rules such as those in /robots.txt.

Additionally, such content being indexed can be removed from Google by consulting Google's Webmaster tools.

An example of indexable content is below:

Search Query: site:https://answers.atlassian.com/upfiles + password
Image of results:

The security risk of this is quite low, however, if sensitive files do lie in /upfiles, they have been indexed by Google and will be easier to find by attackers.