i-doit 'lang' Parameter Local File Include Vulnerability

Summary
This host is running I-doit and is prone to local file inclusion vulnerability.
Impact
Successful exploitation could allow an attacker to gain sensitive information. Impact Level: Application
Solution
No solution or patch was made available for at least one year since disclosure of this vulnerability. Likely none will be provided anymore. General solution options are to upgrade to a newer release, disable respective features, remove the product or replace the product by another one.
Insight
The flaw is caused by improper validation of user supplied input via the 'lang' parameter in 'controller.php', which allows attackers to read arbitrary files via a ../(dot dot) sequences.
Affected
i-doit version 0.9.9-4 and earlier.
References