Directory traversal vulnerability in the web-based management feature on the TP-LINK TL-WR841N router with firmware 3.13.9 build 120201 Rel.54965n and earlier allows remote attackers to read arbitrary files via a .. (dot dot) in the PATH_INFO to the help/ URI.
https://exchange.xforce.ibmcloud.com/vulnerabilities/79662
http://packetstormsecurity.org/files/117749/TP-LINK-TL-WR841N-Local-File-Inclusion.html