CVE-2026-73569: high-severity vulnerability in NaturalIntelligence fast-xml-parser
fast-xml-parser: Repeated DOCTYPE declarations reset entity expansion limits
Published
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7epss 0.5%
fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. From 5.9.3 until 5.10.1, src/xmlparser/OrderedObjParser.js processes multiple DOCTYPE declarations within a single XML document and passes each declaration's entities through addInputEntities(). addInputEntities() resets maxTotalExpansions and maxExpandedLength every time it is called, allowing additional DOCTYPE declarations to repeatedly reset the configured entity-expansion limits during one parse operation. A crafted XML document can then cause excessive CPU use, event-loop blocking, memory exhaustion, and process termination. This issue is fixed in version 5.10.1.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
NaturalIntelligence · fast-xml-parserRelated CVEs — NaturalIntelligence fast-xml-parser
In the same product, most dangerous first.
CVE-2023-34104HIGHRegex Injection via Doctype EntitiesEPSS 1.1%CVE-2026-26278HIGHfast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)EPSS 0.9%CVE-2024-41818HIGHReDOS at currency parsing fast-xml-parserEPSS 0.8%CVE-2026-33036HIGHfast-xml-parser affected by numeric entity expansion bypassing all entity expansion limits (incomplete fix for CVE-2026-26278)EPSS 0.6%CVE-2026-25128HIGHfast-xml-parser has RangeError DoS Numeric Entities BugEPSS 0.6%CVE-2026-27942LOWfast-xml-parser has stack overflow in XMLBuilder with preserveOrderEPSS 0.5%