XWiki Platform vulnerable to privilege escalation (PR) from view right via Invitation application

Impact

Any user with view rights on any document can execute code with programming rights, leading to remote code execution by crafting an url with a dangerous payload. See the example below:
Open <xwiki-host>/xwiki/bin/view/%5D%5D%20%7B%7Basync%20async%3D%22true%22%20cached%3D%22false%22%20context%3D%22doc.reference%22%7D%7D%7B%7Bgroovy%7D%7Dprintln(%22Hello%20%22%20%2B%20%22from%20groovy!%22)%7B%7B%2Fgroovy%7D%7D%7B%7B%2Fasync%7D%7D?sheet=Invitation.InvitationGuestActions&xpage=view where <xwiki-host> is the URL of your XWiki installation.

Patches

The problem as been patching on XWiki 15.0, 14.10.4 and 14.4.8.

Workarounds

It is possible to partially fix the issue by applying this patch. Note that some additional issue can remain and can be fixed automatically by a migration. Hence, it is advised to upgrade to one of the patched version instead of patching manually.

References

• https://jira.xwiki.org/browse/XWIKI-20285

For more information

If you have any questions or comments about this advisory:

• Open an issue in Jira XWiki.org
• Email us at Security Mailing List