Impact

XWiki is vulnerable to reflected cross-site scripting (RXSS) via the rev parameter that is used in the content of the content menu without escaping. If an attacker can convince a user to visit a link with a crafted parameter, this allows the attacker to execute arbitrary actions in the name of the user, including remote code (Groovy) execution in the case of a user with programming right, compromising the confidentiality, integrity and availability of the whole XWiki installation.

The vulnerability can be demonstrated by opening <xwiki-host>/xwiki/bin/view/Main/?rev=xar%3Aorg.xwiki.platform%3Axwiki-platform-distribution-flavor-common%2F15.5%25%25%22%3e%3cscript%3ealert(1)%3c%2fscript%3e where <xwiki-host> is the URL of your XWiki installation. If an alert is displayed, the installation is vulnerable.

Patches

This has been patched in XWiki 15.6 RC1, 15.5.1 and 14.10.14.

Workarounds

The patch can be manually applied without upgrading (or restarting) the instance.

References

• https://jira.xwiki.org/browse/XWIKI-21095
• 04e325d

Attribution

We thank Agostino Parentela, Vulnerability Management Engineer of TicketOne S.p.A., agostino.parentela@ticketone.it for reporting this vulnerability.