Symphony · Symphony Cms · CVE-2017-5542
**Name of the Vulnerable Software and Affected Versions**
Symphony CMS versions prior to 2.6.10
**Description**
A cross-site scripting (XSS) issue exists, allowing remote attackers to inject arbitrary web script or HTML. This is achieved via the `existing-folder` parameter in the template/usererror.missing extension.php file.
**Recommendations**
For versions prior to 2.6.10, update to version 2.6.10 or later to resolve the issue. As a temporary workaround, consider restricting access to the template/usererror.missing extension.php file to minimize the risk of exploitation. Avoid using the `existing-folder` parameter in the affected file until the issue is resolved.