CVE-2023-36471: HTML sanitizer allows form elements in restricted in org.xwiki.commons:xwiki-commons-xml
Impact
The HTML sanitizer that is included in XWiki since version 14.6RC1 allowed form and input HTML tags. In the context of XWiki, this allows an attacker without script right to either create forms that can be used for phishing attacks or also in the context of a sheet, the attacker could add an input like {{html}}<input type="hidden" name="content" value="{{groovy}}println("Hello from Groovy!")" />{{/html}} that would allow remote code execution when it is submitted by an admin (the sheet is rendered as part of the edit form). The attacker would need to ensure that the edit form looks plausible, though, which can be non-trivial as without script right the attacker cannot display the regular content of the document.
Patches This has been patched in XWiki 14.10.6 and 15.2RC1 by removing the central form-related tags from the list of allowed tags.
Workarounds An admin can manually disallow the tags by adding form, input, select, textarea, button to the configuration option xml.htmlElementSanitizer.forbidTags in the xwiki.properties configuration file.
References https://jira.xwiki.org/browse/XCOMMONS-2634 https://github.com/xwiki/xwiki-commons/commit/99484d48e899a68a1b6e33d457825b776c6fe8c3
Other sources
Xwiki commons is the common modules used by other XWiki top level projects. The HTML sanitizer that is included in XWiki since version 14.6RC1 allowed form and input HTML tags. In the context of XWiki, this allows an attacker without script right to either create forms that can be used for phishing attacks or also in the context of a sheet, the attacker could add an input like {{html}}<input type="hidden" name="content" value="{{groovy}}println("Hello from Groovy!")" />{{/html}} that would allow remote code execution when it is submitted by an admin (the sheet is rendered as part of the edit form). The attacker would need to ensure that the edit form looks plausible, though, which can be non-trivial as without script right the attacker cannot display the regular content of the document. This has been patched in XWiki 14.10.6 and 15.2RC1 by removing the central form-related tags from the list of allowed tags. Users are advised to upgrade. As a workaround an admin can manually disallow the tags by adding form, input, select, textarea, button to the configuration option xml.htmlElementSanitizer.forbidTags in the xwiki.properties configuration file.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
maven/org.xwiki.commons:xwiki-commons-xmlto a version that resolves this vulnerability.Fixed in 15.2-rc-1 - Upgrade
Upgrade
maven/org.xwiki.commons:xwiki-commons-xmlto a version that resolves this vulnerability.Fixed in 14.10.6 - Upgrade
Upgrade
org.xwiki.commons:xwiki-commons-xmlto a version that resolves this vulnerability.Fixed in 14.10.6 - Upgrade
Upgrade
org.xwiki.commons:xwiki-commons-xmlto a version that resolves this vulnerability.Fixed in 15.2RC1 - Configuration
As a workaround, in xwiki.properties add these tags to xml.htmlElementSanitizer.forbidTags to manually disallow form and form-related input tags.
XWiki (xwiki.properties) - xml.htmlElementSanitizer.forbidTags xml.htmlElementSanitizer.forbidTags = form, input, select, textarea, button
Event History
Frequently Asked Questions
What is the vulnerability ID of this issue?
The vulnerability ID of this issue is CVE-2023-36471.
What is the severity of CVE-2023-36471?
The severity of CVE-2023-36471 is critical with a CVSS score of 5.4.
What is XWiki Commons?
XWiki Commons is the common modules used by other XWiki top-level projects.
Which versions of XWiki Commons are affected by this vulnerability?
Versions 14.6RC1 to 14.10.6, 15.0, 15.0-rc1, 15.1, and 15.1-rc1 of XWiki Commons are affected by this vulnerability.
What is the impact of this vulnerability?
This vulnerability allows an attacker without script right to either create forms that can be used for phishing.