naturalintelligence/fast-xml-parser · Security
fast-xml-parser has stack overflow in XMLBuilder with preserveOrder
- GHSA ID
- GHSA-fj3w-jwp8-x2g3
- CVE ID
- CVE-2026-27942
- Severity
- low
- Published
- Updated
- CVSS v4
- 2.7 · 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
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
CWEs
- CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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/advisories/GHSA-fj3w-jwp8-x2g3 ↗