VDB
KO
HIGH

GHSA-8r6m-32jq-jx6q

fast-xml-parser: Repeated DOCTYPE declarations reset entity expansion limits

Quick fix

GHSA-8r6m-32jq-jx6q — fast-xml-parser: upgrade to the fixed version with the command below.

npm install fast-xml-parser@5.10.1

Details

### Impact `fast-xml-parser` processes multiple "DOCTYPE" declarations within a single XML document. Each declaration passes its entities to `@nodable/entities` through `addInputEntities()`.

`addInputEntities()` resets the entity expansion counters every time it is called. An attacker can therefore insert additional DOCTYPE declarations to repeatedly reset maxTotalExpansions and maxExpandedLength during one parse operation.

This allows a crafted XML document to exceed the configured entity-expansion limits and can cause excessive CPU use, event-loop blocking, memory exhaustion, and process termination.

### Workarounds - Manually check if multiple DOCTYPEs are not present in input contents - Update to v5.10.1 - Keep `processEntity` flag off

Are you affected?

Enter the version of the package you're using.

Affected packages

npm / fast-xml-parser
Introduced in: 5.9.3 Fixed in: 5.10.1
Fix npm install fast-xml-parser@5.10.1

References