CyberRota Analysis
AI-GeneratedConcrete CMS versions prior to 9.5.4 are vulnerable due to inadequate sanitization of XML and XSLT documents uploaded via a public Form Block, allowing unauthenticated users to store malicious XML files. This can lead to stored cross-site scripting (XSS), where an attacker can execute JavaScript within the context of the Concrete CMS origin, potentially compromising authenticated administrator sessions. Organizations using affected versions should prioritize patching to mitigate the risk of unauthorized access and administrative privilege escalation.
Original NVD Description
Concrete CMS before 9.5.4 did not sanitize XML and XSLT documents uploaded through a public Form Block file-upload question. Plain XML uploads were validated by file extension only and stored as publicly accessible files that were served inline from the application's own origin. An unauthenticated visitor could therefore store an XML document containing an xml-stylesheet processing instruction that referenced an attacker-supplied, same-origin XSLT stylesheet. When a victim opened the stored file directly in a browser, the browser fetched the stylesheet, transformed the document into HTML, and executed attacker-controlled JavaScript in the Concrete CMS origin (stored cross-site scripting). If the victim was an authenticated administrator, the script could act with that administrator's session, and the reporter demonstrated creation of a new user in the Administrators group. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Valentin SARRE (Independent security researcher) for reporting.
Related CVEs
Other vulnerabilities affecting the same vendor(s)