Answer in brief
CVE-2026-73569 records a High severity (CVSS 8.7) vulnerability in fast-xml-parser: Repeated DOCTYPE declarations reset entity expansion limits. The current sources do not mark it as known exploited. The current feed maps NaturalIntelligence/fast-xml-parser (generic), fast-xml-parser (npm), fast-xml-parser (npm). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps NaturalIntelligence/fast-xml-parser (generic), fast-xml-parser (npm), fast-xml-parser (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| NaturalIntelligence/fast-xml-parsergeneric | >=5.9.3 <5.10.1 | 5.10.1 |
| fast-xml-parsernpm | >=5.9.3,<5.10.1 | 5.10.1 |
| fast-xml-parsernpm | >=5.9.3 <5.10.1 | 5.10.1 |
Published upstream
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 13, 2026
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.
Quoted source text, attributed separately from HOL analysis.