XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. When uploading an attachment with a malicious filename, malicious JavaScript code could be executed. This requires a social engineering attack to get the victim into uploading a file with a malicious name. The malicious code is solely executed during the upload and affects only the user uploading the attachment. While this allows performing actions in the name of that user, it seems unlikely that a user wouldn't notice the malicious filename while uploading the attachment. This has been patched in XWiki 14.10.21, 15.5.5, 15.10.6 and 16.0.0.
XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Any user with edit right on any page can perform arbitrary remote code execution by adding instances of `XWiki.SearchSuggestConfig` and `XWiki.SearchSuggestSourceClass` to their user profile or any other page. This compromises the confidentiality, integrity and availability of the whole XWiki installation. This vulnerability has been patched in XWiki 14.10.21, 15.5.5 and 15.10.2.
XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. The content of a document included using `{{include reference="targetdocument"/}}` is executed with the right of the includer and not with the right of its author. This means that any user able to modify the target document can impersonate the author of the content which used the `include` macro. This vulnerability has been patched in XWiki 15.0 RC1 by making the default behavior safe.
XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. When an admin disables a user account, the user's profile is executed with the admin's rights. This allows a user to place malicious code in the user profile before getting an admin to disable the user account. To reproduce, as a user without script nor programming rights, edit the about section of your user profile and add `{{groovy}}services.logging.getLogger("attacker").error("Hello from Groovy!"){{/groovy}}`.
As an admin, go to the user profile and click the "Disable this account" button. Then, reload the page. If the logs show `attacker - Hello from Groovy!` then the instance is vulnerable. This has been patched in XWiki 14.10.21, 15.5.5, 15.10.6 and 16.0.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.
### Workarounds
We're not aware of any workaround except upgrading.
### References
* https://jira.xwiki.org/browse/XWIKI-21611
* https://github.com/xwiki/xwiki-platform/commit/f89c8f47fad6e5cc7e68c69a7e0acde07f5eed5a