GHSA-432c-wxpg-m4q3: Xml2rfc Xml2rfc Has File Inclusion Irregularities Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-432c-wxpg-m4q3",
  "modified" : "2025-02-07T20:32:27Z",
  "published" : "2025-02-07T20:32:27Z",
  "aliases" : [ ],
  "summary" : "xml2rfc has file inclusion irregularities",
  "details" : "Version [3.12.0](https://github.com/ietf-tools/xml2rfc/blob/main/CHANGELOG.md#3120---2021-12-08) changed `xml2rfc` so that it would not access local files without the presence of its new `--allow-local-file-access` flag.\nThis prevented XML External Entity (XXE) injection attacks with `xinclude` and XML entity references.\n\nIt was discovered that `xml2rfc` does not respect `--allow-local-file-access` when a local file is specified as `src` in `artwork` or `sourcecode` elements. Furthermore, XML entity references can include any file inside the source dir and below without using the `--allow-local-file-access` flag. \n\nThe `xml2rfc <= 3.26.0` behaviour:\n\n|  | `xinclude` | XML entity reference | `artwork src=` | `sourcecode src=` |\n|---|---|---|---|---|\n| without `--allow-local-file-access` flag | No filesystem access | Any file in xml2rfc templates dir and below, any file in source directory and below | Access source directory and below | Access source directory and below |\n| with `--allow-local-file-access` flag | Access any file on filesystem[^1] | Access any file on filesystem[^1] | Access source directory and below | Access source directory and below | Access source directory and below |\n\n  [^1]: Access any file of the filesystem with the permissions of the user running `xml2rfc` can access.\n\n### Impact\n\nAnyone running `xml2rfc` as a service that accepts input from external users is impacted by this issue.\nSpecifying a file in `src` attribute in `artwork` or `sourcecode` elements will cause the contents of that file to appear in xml2rfc’s output results.\nBut that file has to be inside the same directory as the XML input source file.\nFor `artwork` and `sourcecode`, `xml2rfc` will not look above the source file directory.\n\n### The proposed new behaviour\n- Generalize file access checks.\n- Only allow access to files within src dir and below. (xml entity include can access templates dir).\n- Always allow access to `templates_dir` for XML entity includes.\n\nNew behaviour:\n\n|  | `xinclude` | XML entity reference | `artwork src=` | `sourcecode src=` |\n|---|---|---|---|---|\n| without `--allow-local-file-access` flag | No filesystem access | No filesystem access _(except for `templates_dir`)_ | No filesystem access | No filesystem access |\n| with `--allow-local-file-access` flag | Access source directory and below | Access source directory and below _(Can access`templates_dir`)._ | Access source directory and below | Access source directory and below |\n\n### Workarounds\n\nUse a secure temporary directory to process un-trusted XML files, and do not reuse it for processing other XML documents.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "xml2rfc"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.12.0"
      }, {
        "fixed" : "3.27.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ietf-tools/xml2rfc/security/advisories/GHSA-432c-wxpg-m4q3"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ietf-tools/xml2rfc/commit/ec98f9cb4b9a8658222117df037dda473ca3f4e4"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ietf-tools/xml2rfc"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-02-07T20:32:27Z",
    "nvd_published_at" : null
  }
}