GitHub Advisoryadvisory · npm

GHSA-fj3w-jwp8-x2g3 fast-xml-parser has stack overflow in XMLBuilder with preserveOrder

LOW Published 2026-02-26 Modified 2026-03-06 Official page ↗
Aliases
CVE-2026-27942
Ecosystem
npm
Packages
fast-xml-parser
Severity
Low
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U
Weaknesses
CWE-120
Reviewed
2026-02-26

Affected packages

• npm fast-xml-parser: >= 5.0.0, < 5.3.8 → fixed in 5.3.8 • npm fast-xml-parser: >= 4.0.0-beta.0, < 4.5.4 → fixed in 4.5.4

Description

Impact Application crashes with stack overflow when user use XML builder with `prserveOrder:true` for following or similar input ``` [{ 'foo': [ { 'bar': [{ '@_V': 'baz' }] } ] }] ``` Cause: `arrToStr` was not validating if the input is an array or a string and treating all non-array values as text content. _What kind of vulnerability is it? Who is impacted?_ Patches Yes in 5.3.8 Workarounds Use XML builder with `preserveOrder:false` or check the input data before passing to builder. References _Are there any links users can visit to find out more?_

Related

Alias · CVE (1)

  • CVE-2026-27942 fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no… vulnerability

Weakness · CWE (1)

  • CWE-120 Buffer Copy without Checking Size of Input weakness

References