Vulnerability · Published Aug 13, 2026 · Assigned by GitHub_M
CVE-2026-73569fast-xml-parser: Repeated DOCTYPE declarations reset entity expansion limits
High 8.7
In plain English
A high-severity security flaw in fast-xml-parser from NaturalIntelligence. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | node-webfont | no fix listed | DEBIAN-CVE-2026-73569 |
| Debian:14 | node-webfont | no fix listed | DEBIAN-CVE-2026-73569 |
| Ubuntu:24.04:LTS | node-webfont | no fix listed | UBUNTU-CVE-2026-73569 |
| Ubuntu:26.04:LTS | node-webfont | no fix listed | UBUNTU-CVE-2026-73569 |
| Ubuntu:26.10 | node-webfont | no fix listed | UBUNTU-CVE-2026-73569 |
| npm | fast-xml-parser | 5.10.1 | GHSA-8r6m-32jq-jx6q |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| NaturalIntelligence | fast-xml-parser | >= 5.9.3, < 5.10.1 |
Weakness: CWE-776 · Vector: 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
References
- https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-8r6m-32jq-jx6q x_refsource_CONFIRM
- https://github.com/NaturalIntelligence/fast-xml-parser/commit/4e546e03987662de5495d050b5fba26bea65383f x_refsource_MISC
- https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.10.1 x_refsource_MISC