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Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in org.xwiki.commons:xwiki-commons-xml

Critical
tmortagne published GHSA-m3jr-cvhj-f35j Apr 12, 2023

Package

maven org.xwiki.commons:xwiki-commons-xml (Maven)

Affected versions

>= 4.2-milestone-1

Patched versions

14.6-rc-1

Description

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:

{{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

For more information

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Severity

Critical
9.0
/ 10

CVSS base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

CVE ID

CVE-2023-29201