Horde Webmail 'url' Parameter Open Redirect Vulnerability

Summary
This host is installed Horde Webmail and is prone to open redirect vulnerability.
Impact
Successful exploitation will allow remote attackers to create a specially crafted URL, that if clicked, would redirect a victim from the intended legitimate web site to an arbitrary web site of the attacker's choosing. Impact Level: Application
Solution
No solution or patch is available as of 20th February, 2015. Information regarding this issue will be updated once the solution details are available. For updates refer to http://www.horde.org/apps/webmail
Insight
The flaw exists because the application does not validate the 'url' parameter upon submission to the /horde/util/go.php script.
Affected
Horde Webmail version 5.1 and prior
Detection
Send a crafted HTTP GET request and check whether it redirects to the malicious websites.
References