Title:Concrete CMS 9 through 9.4.2 and below 8.5.21 is vulnerable to Reflected Cross-Site Scripting (XSS) in Conversation Messages Dashboard Page (CVE-2025-8571) Description:Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Fortbridge https://fortbridge.co.uk/ for performing a penetration test and vulnerability assessment on Concrete CMS and reporting this issue.
1. It is advised to access via the original source first.2. Local POC snapshots are reserved for subscribers — if the original source is unavailable, the local mirror is part of the paid plan.3. Mirroring, verifying, and maintaining this POC archive takes ongoing effort, so local snapshots are a paid feature. Your subscription keeps the archive online — thank you for the support. View subscription plans →