Concrete CMS versions 9.0.0 to 9.3.3 and below 8.5.19 are vulnerable to Stored XSS in Image Editor Background Color.  A rogue admin could add malicious code to the Thumbnails/Add-Type. The Concrete CMS Security Team gave this a CVSS v4 score of 2.1 with vector CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N  Thanks,  Alexey Solovyev for reporting.