Description Contao >=4.0.0 allows backend XSS via HTML attributes to an HTML field. Fixed in 4.4.56, 4.9.18, 4.11.7. Remediation References CVE-2021-35955 Related Vulnerabilities MySQL CVE-2024-21125 Vulnerability (CVE-2024-21125) Oracle Database Server Other Vulnerability (CVE-2005-3641) WordPress Plugin Online Hotel Booking System Pro SQL Injection (1.0) PHP Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability (CVE-2007-1381) SharePoint Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') Vulnerability (CVE-2026-47640) Severity Medium Classification CVE-2021-35955 CWE-707 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N Tags Missing Update Known Vulnerabilities