Path Traversal: '/dir/../filename'
CWE-26 · Variant · Draft
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize "/dir/../filename" sequences that can resolve to a location that is outside of that directory.
Extended description
This allows attackers to traverse the file system to access files or directories that are outside of the restricted directory. The '/dir/../filename' manipulation is useful for bypassing some path traversal protection schemes. Sometimes a program only checks for "../" at the beginning of the input, so a "/../" can bypass that check.