{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "fast-xml-parser"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.2.4"
            },
            {
              "fixed": "4.2.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.2.4"
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": true,
    "github_reviewed_at": "2023-06-15T19:05:13Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Summary\nThis is a comment on https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-6w63-h3fj-q4vw and the patches fixing it.\n\n### Details\nThe code which validates a name calls the validator:\nhttps://github.com/NaturalIntelligence/fast-xml-parser/blob/ecf6016f9b48aec1a921e673158be0773d07283e/src/xmlparser/DocTypeReader.js#L145-L153\nThis checks for the presence of an invalid character.  Such an approach is always risky, as it is so easy to forget to include an invalid character in the list.  A safer approach is to validate entity names against the XML specification: https://www.w3.org/TR/xml11/#sec-common-syn - an ENTITY name is a Name:\n\n```\n[4]   NameStartChar ::= \":\" | [A-Z] | \"_\" | [a-z] | [#xC0-#xD6] | [#xD8-#xF6] | [#xF8-#x2FF] | [#x370-#x37D] |\n                        [#x37F-#x1FFF] | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF] |\n                        [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF]\n[4a]  NameChar ::= NameStartChar | \"-\" | \".\" | [0-9] | #xB7 | [#x0300-#x036F] | [#x203F-#x2040]\n[5]   Name ::= NameStartChar (NameChar)*\n```\n\nso the safest way to validate an entity name is to build a regex to represent this expression and check whether the name given matches the regex.  (Something along the lines of `/^[name start char class][name char class]*$/`.)  There\u0027s probably a nice way to simplify the explicit list rather than typing it out verbatim using Unicode character properties, but I don\u0027t know enough to do so.",
  "id": "GHSA-gpv5-7x3g-ghjv",
  "modified": "2023-06-15T19:05:13Z",
  "published": "2023-06-15T19:05:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-6w63-h3fj-q4vw"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-gpv5-7x3g-ghjv"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NaturalIntelligence/fast-xml-parser/commit/9a880b887916855c3a510869fd1ee268d7fe58b1"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/NaturalIntelligence/fast-xml-parser"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [],
  "summary": "fast-xml-parser regex vulnerability patch could be improved from a safety perspective"
}