The safe_path function in shttp before 0.0.5 allows remote attackers to conduct directory traversal attacks and read files via a combination of ".." and sub-directory specifiers that resolve to a pathname that is at or below the same level as the web document root, but in a different part of the directory tree.
https://exchange.xforce.ibmcloud.com/vulnerabilities/37455
http://www.securityfocus.com/archive/1/482797/100/0/threaded
http://www.digineo.co.uk/shttp_directory_traversal
http://serverkit.org/modules/contrib/shttp/shttp-0.0.5.tar.gz