wget 1.8.x and 1.9.x allows a remote malicious web server to overwrite certain files via a redirection URL containing a ".." that resolves to the IP address of the malicious server, which bypasses wget's filtering for ".." sequences.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11682
https://exchange.xforce.ibmcloud.com/vulnerabilities/18420
http://www.redhat.com/support/errata/RHSA-2005-771.html