CVE-2026-73569
Received
Received - Intake
fast-xml-parser Billion Laughs DoS via DOCTYPE Expansion
Vulnerability report for CVE-2026-73569, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-08-13
Last updated on: 2026-08-13
Assigner: GitHub, Inc.
Description
Description
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 Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| naturalintelligence | fast-xml-parser | From 5.9.3 (inc) to 5.10.1 (inc) |
| naturalintelligence | fast-xml-parser | 5.10.1 |
| fast-xml-parser | fast-xml-parser | From 5.9.3 (inc) to 5.10.1 (inc) |
| fast-xml-parser | fast-xml-parser | 5.10.1 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-776 | The product uses XML documents and allows their structure to be defined with a Document Type Definition (DTD), but it does not properly control the number of recursive definitions of entities. |
