CVE-2026-27942
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
Package Versions Affected
Automatically patch vulnerabilities without upgrading
CVSS Version



Related Resources
References
https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-fj3w-jwp8-x2g3, https://nvd.nist.gov/vuln/detail/CVE-2026-27942, https://github.com/NaturalIntelligence/fast-xml-parser/pull/791, https://github.com/NaturalIntelligence/fast-xml-parser/commit/c13a961910f14986295dd28484eee830fa1a0e8a, https://github.com/NaturalIntelligence/fast-xml-parser
