Description
XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. In affected versions any user with view rights can execute arbitrary Groovy, Python or Velocity code in XWiki leading to full access to the XWiki installation. The root cause is improper escaping of UIX parameters. A proof of concept exploit is to log in, add an `XWiki.UIExtensionClass` xobject to the user profile page, with an Extension Parameters content containing `label={{/html}} {{async async="true" cached="false" context="doc.reference"}}{{groovy}}println("Hello " + "from groovy!"){{/groovy}}{{/async}}`. Then, navigating to `PanelsCode.ApplicationsPanelConfigurationSheet` (i.e., `
Remediation
References
https://github.com/xwiki/xwiki-platform/commit/6de5442f3c91c3634a66c7b458d5b142e1c2a2dc
https://github.com/xwiki/xwiki-platform/security/advisories/GHSA-qxjg-jhgw-qhrv
https://jira.xwiki.org/browse/XWIKI-20294