pyftpdlib FTP Server Denial of Service Vulnerability

Summary
This host is running pyftpdlib FTP server and is prone to Denial of Service vulnerability.
Impact
Successful exploitation will allow attacker to cause a denial of service. Impact Level: Application
Solution
Upgrade to pyftpdlib version 0.5.2 or later, For updates refer to http://code.google.com/p/pyftpdlib/downloads/list
Insight
The flaw is due to race condition in the FTPHandler class, which allows remote attackers to cause a denial of service by establishing and then immediately closing a TCP connection, leading to the accept function having an unexpected return value of None.
Affected
ftpserver.py in pyftpdlib before 0.5.1
References