Advisory by Netsparker.
Name: Multiple XSS Vulnerabilities in Concrete5
Affected Software : Concrete5
Affected Versions: and possibly below
Vendor Homepage :
Vulnerability Type : Cross-site Scripting
Severity : Important
CVE-ID: CVE-2015-2250
Netsparker Advisory Reference : NS-15-008

Technical Details
Proof of Concept URLs for XSS in Concrete5:

For more information on cross-site scripting vulnerabilities read the article Cross-site Scripting (XSS).

Advisory Timeline
05/03/2015 - First Contact
06/05/2015 - Vulnerability fixed
11/05/2015 - Advisory released

Download Concrete5 version 5.7.4 which includes fix for this vulnerability.

Credits & Authors
These issues have been discovered by Omar Kurt while testing Netsparker Web Application Security Scanner.

About Netsparker
Netsparker finds and reports security flaws and vulnerabilities such as SQL Injection and Cross-site Scripting (XSS) in all websites and web applications regardless of the platform and the technology they are built on. Netsparker's unique detection and exploitation techniques allow it to be dead accurate in reporting vulnerabilities, hence it is the first and only False Positive Free web application security scanner.