fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)_CVE-2026-26278

{
    "lastseen": "",
    "description": "fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. In versions 4.1.3 through 5.3.5, the XML parser can be forced to do an unlimited amount of entity expansion. With a very small XML input, it\u2019s possible to make the parser spend seconds or even minutes processing a single request, effectively freezing the application. Version 5.3.6 fixes the issue. As a workaround, avoid using DOCTYPE parsing by `processEntities: false` option.",
    "published": "2026-02-19T19:40:55.842Z",
    "modified": "2026-02-19T19:40:55.842Z",
    "type": "cve",
    "title": "fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)",
    "source": "GitHub_M",
    "references": "https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-jmr7-xgp7-cmfj\nhttps://github.com/NaturalIntelligence/fast-xml-parser/commit/910dae5be2de2955e968558fadf6e8f74f117a77\nhttps://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.6",
    "id": "CVE-2026-26278",
    "bulletinFamily": "",
    "cwe": [
        "CWE-776"
    ],
    "cvelist": null,
    "sourceData": "NaturalIntelligence fast-xml-parser >= 4.1.3, < 5.3.6",
    "sourceHref": "",
    "cvss": {
        "score": 7.5,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "fast-xml-parser",
    "version": ">= 4.1.3, < 5.3.6",
    "vendor": "NaturalIntelligence",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}