CVE-2023-37908

XWiki Rendering is a generic Rendering system that converts textual input in a given syntax into another syntax. The cleaning of attributes during XHTML rendering, introduced in version 14.6-rc-1, allowed the injection of arbitrary HTML code and thus cross-site scripting via invalid attribute names. This can be exploited, e.g., via the link syntax in any content that supports XWiki syntax like comments in XWiki. When a user moves the mouse over a malicious link, the malicious JavaScript code is executed in the context of the user session. When this user is a privileged user who has programming rights, this allows server-side code execution with programming rights, impacting the confidentiality, integrity and availability of the XWiki instance. While this attribute was correctly recognized as not allowed, the attribute was still printed with a prefix `data-xwiki-translated-attribute-` without further cleaning or validation. This problem has been patched in XWiki 14.10.4 and 15.0 RC1 by removing characters not allowed in data attributes and then validating the cleaned attribute again. There are no known workarounds apart from upgrading to a version including the fix.

XWiki Rendering is a generic Rendering system that converts textual input in a given syntax into another syntax. The cleaning of attributes during XHTML rendering, introduced in version 14.6-rc-1, allowed the injection of arbitrary HTML code and thus cross-site scripting via invalid attribute names. This can be exploited, e.g., via the link syntax in any content that supports XWiki syntax like comments in XWiki. When a user moves the mouse over a malicious link, the malicious JavaScript code is executed in the context of the user session. When this user is a privileged user who has programming rights, this allows server-side code execution with programming rights, impacting the confidentiality, integrity and availability of the XWiki instance. While this attribute was correctly recognized as not allowed, the attribute was still printed with a prefix `data-xwiki-translated-attribute-` without further cleaning or validation. This problem has been patched in XWiki 14.10.4 and 15.0 RC1 by removing characters not allowed in data attributes and then validating the cleaned attribute again. There are no known workarounds apart from upgrading to a version including the fix.

### Impact The cleaning of attributes during XHTML rendering, introduced in version 14.6-rc-1, allowed the injection of arbitrary HTML code and thus cross-site scripting via invalid attribute names. This can be exploited, e.g., via the link syntax in any content that supports XWiki syntax like comments in XWiki: ``` [[Link1>>https://XWiki.example.com||/onmouseover="alert('XSS1')"]] ``` When a user moves the mouse over this link, the malicious JavaScript code is executed in the context of the user session. When this user is a privileged user who has programming rights, this allows server-side code execution with programming rights, impacting the confidentiality, integrity and availability of the XWiki instance. While this attribute was correctly recognized as not allowed, the attribute was still printed with a prefix `data-xwiki-translated-attribute-` without further cleaning or validation. Note that while versions below 14.6 are not vulnerable to this particular vulnerability, they are still vulnerable to XSS through attributes in XWiki syntax, see [the corresponding advisory](https://github.com/xwiki/xwiki-rendering/security/advisories/GHSA-6gf5-c898-7rxp). ### Patches This problem has been patched in XWiki 14.10.4 and 15.0 RC1 by removing characters not allowed in data attributes and then validating the cleaned attribute again. ### Workarounds There are no known workarounds apart from upgrading to a version including the fix. ### References * https://jira.xwiki.org/browse/XRENDERING-697 * https://github.com/xwiki/xwiki-rendering/commit/f4d5acac451dccaf276e69f0b49b72221eef5d2f ### For more information If you have any questions or comments about this advisory: * Open an issue in [Jira XWiki](https://jira.xwiki.org/) * Email us at [XWiki Security mailing-list](mailto:security@xwiki.org)

### Impact The cleaning of attributes during XHTML rendering, introduced in version 14.6-rc-1, allowed the injection of arbitrary HTML code and thus cross-site scripting via invalid attribute names. This can be exploited, e.g., via the link syntax in any content that supports XWiki syntax like comments in XWiki: ``` [[Link1>>https://XWiki.example.com||/onmouseover="alert('XSS1')"]] ``` When a user moves the mouse over this link, the malicious JavaScript code is executed in the context of the user session. When this user is a privileged user who has programming rights, this allows server-side code execution with programming rights, impacting the confidentiality, integrity and availability of the XWiki instance. While this attribute was correctly recognized as not allowed, the attribute was still printed with a prefix `data-xwiki-translated-attribute-` without further cleaning or validation. Note that while versions below 14.6 are not vulnerable to this particular vulnerability, they are still vulnerable to XSS through attributes in XWiki syntax, see [the corresponding advisory](https://github.com/xwiki/xwiki-rendering/security/advisories/GHSA-6gf5-c898-7rxp). ### Patches This problem has been patched in XWiki 14.10.4 and 15.0 RC1 by removing characters not allowed in data attributes and then validating the cleaned attribute again. ### Workarounds There are no known workarounds apart from upgrading to a version including the fix. ### References * https://jira.xwiki.org/browse/XRENDERING-697 * https://github.com/xwiki/xwiki-rendering/commit/f4d5acac451dccaf276e69f0b49b72221eef5d2f ### For more information If you have any questions or comments about this advisory: * Open an issue in [Jira XWiki](https://jira.xwiki.org/) * Email us at [XWiki Security mailing-list](mailto:security@xwiki.org)

XWiki Rendering es un sistema de renderizado genérico que convierte la entrada de texto en una sintaxis determinada en otra sintaxis. La limpieza de atributos durante la representación XHTML, introducida en la versión 14.6-rc-1, permitió la inyección de código HTML arbitrario y, por lo tanto, Cross-Site Scripting (XSS) a través de nombres de atributos no válidos. Esto se puede explotar, por ejemplo, a través de la sintaxis de enlace en cualquier contenido que admita la sintaxis XWiki, como comentarios en XWiki. Cuando un usuario mueve el mouse sobre un enlace malicioso, el código JavaScript malicioso se ejecuta en el contexto de la sesión del usuario. Cuando este usuario es un usuario privilegiado que tiene derechos de programación, esto permite la ejecución de código del lado del servidor con derechos de programación, lo que afecta la confidencialidad, integridad y disponibilidad de la instancia de XWiki. Si bien este atributo se reconoció correctamente como no permitido, aún así se imprimió con un prefijo `data-xwiki-translated-attribute-` sin más limpieza o validación. Este problema se solucionó en XWiki 14.10.4 y 15.0 RC1 eliminando caracteres no permitidos en los atributos de datos y luego validando el atributo limpio nuevamente. No se conocen workarounds aparte de actualizar a una versión que incluya la solución.