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 Joomla! Core 1.6.x Cross-Site Scripting (1.6.0 - 1.6.3) WordPress Plugin WordPress Social Login and Register (Discord, Google, Twitter, LinkedIn) Unspecified Vulnerability (5.1) Joomla Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') Vulnerability (CVE-2011-4909) WordPress Plugin Ultimate Member-User Profile, Registration, Login, Member Directory, Content Restriction & Membership Cross-Site Scripting (2.4.0) WordPress Plugin WP htaccess Control Unspecified Vulnerability (2.4) 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