The following issue was discovered in Drupal's freelinking module:

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The freelinking and freelinking case tracker modules implement a filter for the easier creation of HTML links to other pages in the site or external sites with a wiki style format such as [[pluginname:identifier]].

The module doesn't sufficiently check access to content when displaying links to nodes and users. This makes it possible to see node titles, usernames and potentially other data depending on the site configuration.

This vulnerability is mitigated by the fact that a site must use node access or permissions to prevent some users from viewing some nodes or users.
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A patch is not available as the module is no longer maintained. drupal6-freelinking is available in Fedora 19, but not in Fedora 20.

References:

https://www.drupal.org/node/2308503