{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.8.0"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "f48e36d2052bcae56081bee3c281bfc69fe7f70d"
            }
          ],
          "repo": "https://github.com/hedgedoc/hedgedoc",
          "type": "GIT"
        }
      ]
    }
  ],
  "details": "HedgeDoc (formerly known as CodiMD) is an open-source collaborative markdown editor. An attacker can read arbitrary `.md` files from the server's filesystem due to an improper input validation, which results in the ability to perform a relative path traversal. To verify if you are affected, you can try to open the following URL: `http://localhost:3000/..%2F..%2FREADME#` (replace `http://localhost:3000` with your instance's base-URL e.g. `https://demo.hedgedoc.org/..%2F..%2FREADME#`). If you see a README page being rendered, you run an affected version. The attack works due the fact that the internal router passes the url-encoded alias to the `noteController.showNote`-function. This function passes the input directly to findNote() utility function, that will pass it on the the parseNoteId()-function, that tries to make sense out of the noteId/alias and check if a note already exists and if so, if a corresponding file on disk was updated. If no note exists the note creation-function is called, which pass this unvalidated alias, with a `.md` appended, into a path.join()-function which is read from the filesystem in the follow up routine and provides the pre-filled content of the new note. This allows an attacker to not only read arbitrary `.md` files from the filesystem, but also observes changes to them. The usefulness of this attack can be considered limited, since mainly markdown files are use the file-ending `.md` and all markdown files contained in the hedgedoc project, like the README, are public anyway. If other protections such as a chroot or container or proper file permissions are in place, this attack's usefulness is rather limited. On a reverse-proxy level one can force a URL-decode, which will prevent this attack because the router will not accept such a path.",
  "id": "CVE-2021-29474",
  "modified": "2026-03-13T21:53:33.894417437Z",
  "published": "2021-04-26T22:15:08.900Z",
  "references": [
    {
      "type": "FIX",
      "url": "https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-p528-555r-pf87"
    }
  ],
  "related": [
    "GHSA-p528-555r-pf87"
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}