WordPress Twenty Fifteen 4.2.1 Cross Site Scripting

`Information  
--------------------  
Advisory by Netsparker.  
Name: DOM XSS Vulnerability in Twenty Fifteen WordPress Theme  
Affected Software : WordPress  
Affected Versions: 4.2.1 and probably below  
Vendor Homepage : https://wordpress.org/ and  
https://wordpress.org/themes/twentyfifteen/  
Vulnerability Type : DOM based Cross-site Scripting  
Severity : Important  
CVE-ID: CVE-2015-3429  
Netsparker Advisory Reference : NS-15-007  
  
Description  
--------------------  
By exploiting a Cross-site scripting vulnerability the attacker can  
hijack a logged in user’s session. This means that the malicious  
hacker can change the logged in user’s password and invalidate the  
session of the victim while the hacker maintains access. As seen from  
the XSS example in this article, if a web application is vulnerable to  
cross-site scripting and the administrator’s session is hijacked, the  
malicious hacker exploiting the vulnerability will have full admin  
privileges on that web application.  
  
Technical Details  
--------------------  
Proof of Concept URL for DOM XSS in WordPress:  
  
http://example.com/wordpress/wp-content/themes/twentyfifteen/genericons/example.html#<img/src/onerror=alert(123)>  
  
For more information on DOM based cross-site scripting vulnerabilities  
read the following article:  
https://www.netsparker.com/blog/web-security/dom-based-cross-site-scripting-vulnerability/  
  
Advisory Timeline  
--------------------  
22/04/2015 - First Contact  
07/05/2015 - Vulnerability fixed  
07/05/2014 - Advisory released  
  
Solution  
--------------------  
Download WordPress version 4.2.2 which includes fix for this vulnerability.  
  
Credits & Authors  
--------------------  
These issues have been discovered by Omar Kurt while testing  
Netsparker Web Application Security Scanner -  
https://www.netsparker.com/web-vulnerability-scanner/  
  
About Netsparker  
--------------------  
Netsparker finds and reports 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. Netsparker'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. For more information visit our website on  
https://www.netsparker.com  
`