GHSA-fj3w-jwp8-x2g3
fast-xml-parser has stack overflow in XMLBuilder with preserveOrder
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | fast-xml-parser | >= 5.0.0, < 5.3.8 | 5.3.8 |
| npm | fast-xml-parser | >= 4.0.0-beta.0, < 4.5.4 | 4.5.4 |
Details
As written in the advisory (Markdown source, shown as plain text).
### 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?_](https://github.com/NaturalIntelligence/fast-xml-parser/pull/791)
References
External links from the advisory. They lead to third-party sites.
- 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