High 8.7Published Aug 13, 2026

CVE-2026-73569fast-xml-parser: Repeated DOCTYPE declarations reset entity expansion limits

Updated under an hour ago (2026-10-19 06:20 UTC)

Does this affect you?

It affects NaturalIntelligence fast-xml-parser. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for NaturalIntelligence fast-xml-parser

Exploited in the last 30 days

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: 8.7 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-776
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Aug 13, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

NaturalIntelligence fast-xml-parser naturalintelligence:fast_xml_parser (from the name)	from 5.9.3, < 5.10.1	CNA record

References

https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-8r6m-32jq-jx6qx-refsource-confirm
https://github.com/NaturalIntelligence/fast-xml-parser/commit/4e546e03987662de5495d050b5fba26bea65383fx-refsource-misc
https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.10.1x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.