id: GO-2022-1143
modules:
    - module: std
      versions:
        - fixed: 1.18.9
        - introduced: 1.19.0-0
        - fixed: 1.19.4
      vulnerable_at: 1.19.3
      packages:
        - package: os
          goos:
            - windows
          symbols:
            - dirFS.Open
            - dirFS.Stat
            - DirFS
        - package: net/http
          goos:
            - windows
          symbols:
            - Dir.Open
          derived_symbols:
            - ServeFile
            - fileHandler.ServeHTTP
            - fileTransport.RoundTrip
summary: Restricted file access on Windows in os and net/http
description: |-
    On Windows, restricted files can be accessed via os.DirFS and http.Dir.

    The os.DirFS function and http.Dir type provide access to a tree of files rooted
    at a given directory. These functions permit access to Windows device files
    under that root. For example, os.DirFS("C:/tmp").Open("COM1") opens the COM1
    device. Both os.DirFS and http.Dir only provide read-only filesystem access.

    In addition, on Windows, an os.DirFS for the directory (the root of the current
    drive) can permit a maliciously crafted path to escape from the drive and access
    any path on the system.

    With fix applied, the behavior of os.DirFS("") has changed. Previously, an empty
    root was treated equivalently to "/", so os.DirFS("").Open("tmp") would open the
    path "/tmp". This now returns an error.
references:
    - report: https://go.dev/issue/56694
    - fix: https://go.dev/cl/455716
    - web: https://groups.google.com/g/golang-announce/c/L_3rmdT0BMU/m/yZDrXjIiBQAJ
cve_metadata:
    id: CVE-2022-41720
    cwe: 'CWE 22: Improper Limitation of a Pathname to a Restricted Directory (''Path Traversal'')'
review_status: REVIEWED