CVE-2025-53835: XWiki Rendering is vulnerable to XSS attacks through insecure XHTML syntax
Impact The XHTML syntax depended on the xdom+xml/current syntax which allows the creation of raw blocks that permit the insertion of arbitrary HTML content including JavaScript. This allows XSS attacks for users who can edit a document like their user profile (enabled by default). The attack works by setting the document's syntax to xdom+xml/current and then inserting content like <document><p><metadata><metadata><entry><string>syntax</string><org.xwiki.rendering.syntax.Syntax><type><name>XHTML</name><id>xhtml</id><variants class="empty-list"></variants></type><version>5</version></org.xwiki.rendering.syntax.Syntax></entry></metadata></metadata></p><rawtext syntax="html/5.0" content="<script>alert(1);</script>"></rawtext></document>
This has been fixed by removing the dependency on the xdom+xml/current syntax from the XHTML syntax. Note that the xdom+xml syntax is still vulnerable to this attack. As it's main purpose is testing and its use is quite difficult, this syntax shouldn't be installed or used on a regular wiki. We're currently not aware of any further dependencies on it.
Patches The fix of removing the dependency has been included in XWiki 14.10. It is not released for earlier versions due to the potential breakages, among others this change makes it necessary to update the Confluence XHTML syntax as it relies on internals that were changed for the fix. Similar XSS fixes were also not applied to the LTS version 13.10.x due to the potential breakages.
Workarounds There are no known workarounds apart from upgrading.
References https://jira.xwiki.org/browse/XRENDERING-660 https://github.com/xwiki/xwiki-rendering/commit/a4ca31f99f524b9456c64150d6f375984aa81ea7
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
Other sources
XWiki Rendering is a generic rendering system that converts textual input in a given syntax (wiki syntax, HTML, etc) into another syntax (XHTML, etc). Starting in version 5.4.5 and prior to version 14.10, the XHTML syntax depended on the xdom+xml/current syntax which allows the creation of raw blocks that permit the insertion of arbitrary HTML content including JavaScript. This allows XSS attacks for users who can edit a document like their user profile (enabled by default). This has been fixed in version 14.10 by removing the dependency on the xdom+xml/current syntax from the XHTML syntax. Note that the xdom+xml syntax is still vulnerable to this attack. As it's main purpose is testing and its use is quite difficult, this syntax shouldn't be installed or used on a regular wiki. There are no known workarounds apart from upgrading.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-53835?
The severity of CVE-2025-53835 has been classified as critical due to its potential for XSS attacks.
How do I fix CVE-2025-53835?
To fix CVE-2025-53835, upgrade the affected package to version 14.10 or later.
What software is affected by CVE-2025-53835?
CVE-2025-53835 affects the 'org.xwiki.rendering:xwiki-rendering-syntax-xhtml' package versions from 5.4.5 up to (but not including) 14.10.
What type of vulnerability is CVE-2025-53835?
CVE-2025-53835 is a cross-site scripting (XSS) vulnerability that allows arbitrary HTML content and JavaScript to be inserted.
Who is at risk for CVE-2025-53835?
Users who can edit documents, such as their user profile, are at risk for CVE-2025-53835 due to the ability to exploit this vulnerability.