{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "4.0.0-beta.3"
              },
              {
                "last_affected": "5.5.5"
              }
            ]
          },
          "events": [
            {
              "introduced": "7439272f2a98f8a551de7a105faeab58c6fbf74a"
            },
            {
              "last_affected": "e54155f53048e9d58e27f170d3ccff15176b6671"
            }
          ],
          "repo": "https://github.com/NaturalIntelligence/fast-xml-parser",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "bd26122c838e6a55e7d7ac49b4ccc01a49999a01"
            },
            {
              "fixed": "870043e75e78545192bc70950c6286d36c7cdf23"
            }
          ],
          "repo": "https://github.com/naturalintelligence/fast-xml-parser",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-8gc5-j5rx-235r"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-776"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33036.json"
  },
  "details": "fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Versions 4.0.0-beta.3 through 5.5.5 contain a bypass vulnerability where numeric character references (\u0026#NNN;, \u0026#xHH;) and standard XML entities completely evade the entity expansion limits (e.g., maxTotalExpansions, maxExpandedLength) added to fix CVE-2026-26278, enabling XML entity expansion Denial of Service. The root cause is that replaceEntitiesValue() in OrderedObjParser.js only enforces expansion counting on DOCTYPE-defined entities while the lastEntities loop handling numeric/standard entities performs no counting at all. An attacker supplying 1M numeric entity references like \u0026#65; can force ~147MB of memory allocation and heavy CPU usage, potentially crashing the process—even when developers have configured strict limits. This issue has been fixed in version 5.5.6.",
  "id": "CVE-2026-33036",
  "modified": "2026-04-01T23:10:32.477973049Z",
  "published": "2026-03-20T05:17:03.290Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.5.6"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33036.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-8gc5-j5rx-235r"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33036"
    },
    {
      "type": "FIX",
      "url": "https://github.com/NaturalIntelligence/fast-xml-parser/commit/bd26122c838e6a55e7d7ac49b4ccc01a49999a01"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "fast-xml-parser affected by numeric entity expansion bypassing all entity expansion limits (incomplete fix for CVE-2026-26278)"
}