org.xwiki.commons:xwiki-commons-xml Cross-site Scripting vulnerability
Date: 2023-04
Affected: maven/org.xwiki.commons:xwiki-commons-xml
Attack vector: xss
Category: vulnerability-disclosure
Severity: Critical
CVE: CVE-2023-29201
CWE: CWE-79
CVSS: 9 (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H)

### Impact The "restricted" mode of the HTML cleaner in XWiki, introduced in version 4.2-milestone-1, only escaped `<script>` and `<style>`-tags but neither attributes that can be used to inject scripts nor other dangerous HTML tags like `<iframe>`. As a consequence, any code relying on this "restricted" mode for security is vulnerable to JavaScript injection ("cross-site scripting"/XSS). An example are anonymous comments in XWiki where the HTML macro filters HTML using restricted mode: ```javascript {{html}} <a href='' onclick='alert(1)'>XSS</a> {{/html}} ``` When a privileged user with programming rights visits such a comment in XWiki, the malicious JavaScript code is executed in the context of the user session. This allows server-side code execution with programming rights, impacting the confidentiality, integrity and availability of the XWiki instance. ### Patches This problem has been patched in XWiki 14.6 RC1 with the introduction of a filter with allowed HTML elements and attributes that is enabled in restricted mode. ### Workarounds There are no known workarounds apart from upgrading to a version including the fix. ### References * https://github.com/xwiki/xwiki-commons/commit/b11eae9d82cb53f32962056b5faa73f3720c6182 - the patch with the filter * https://github.com/xwiki/xwiki-commons/commit/4a185e0594d90cd4916d60aa60bb4333dc5623b2 - the patch with the definitions what is allowed * https://jira.xwiki.org/browse/XWIKI-9118 - the security issue with the HTML macro


Mitigations:

Architectural layers (MAESTRO):