published September 15, 2026
Concrete CMS before 9.5.3 rendered Express entry labels as raw HTML when displaying associated entries, resulting in stored cross-site scripting. An unauthenticated attacker could submit a payload through a public Express Form; it then executed in an administrator's dashboard session when the associated entry was viewed, or in the browser of any visitor to a page using an Express Entry List block with association columns, allowing actions to be performed with that user's privileges. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks v01demort for reporting.