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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-x37v-36wv-6v6h Apr 20, 2023

Package

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

Affected versions

>= 4.2-milestone-1, < 14.10

Patched versions

14.10

Description

Impact

The "restricted" mode of the HTML cleaner in XWiki, introduced in version 4.2-milestone-1 and massively improved in version 14.6-rc-1, allowed the injection of arbitrary HTML code and thus cross-site scripting via invalid HTML comments. 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}}
<!--> <Details Open OnToggle=confirm("XSS")>
{{/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.

Note that while all versions since 4.2-milestone-1 should be vulnerable, only starting with version 14.6-rc-1 the HTML comment is necessary for the attack to succeed due to another vulnerability that has been patched in version 14.6-rc-1.

Patches

This problem has been patched in XWiki 14.10, HTML comments are now removed in restricted mode and a check has been introduced that ensures that comments don't start with >.

Workarounds

There are no known workarounds apart from upgrading to a version including the fix.

References

For more information

If you have any questions or comments about this advisory:

Attribution

This vulnerability was reported on Intigriti by ynoof @Ynoof5.

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-2023-29528

Weaknesses

Credits