The XWiki JIRA extension allows data leak through an XXE attack by using a fake JIRA server

The XWiki JIRA extension provides various integration points between XWiki and JIRA (macros, UI, CKEditor plugin). If the JIRA macro is installed, any logged in XWiki user could edit his/her user profile wiki page and use that JIRA macro, specifying a fake JIRA URL that returns an XML specifying a DOCTYPE pointing to a local file on the XWiki server host and displaying that file's content in one of the returned JIRA fields (such as the summary or description for example). The vulnerability has been patched in the JIRA Extension v8.6.5.