CVE-2026-27942
Description
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 callback. Prior to version 5.3.8, the application crashes with stack overflow when user use XML builder with `preserveOrder:true`. Version 5.3.8 fixes the issue. As a workaround, use XML builder with `preserveOrder:false` or check the input data before passing to builder.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | bookworm | undetermined | |
| debian | forky | undetermined | |
| debian | sid | undetermined | |
| debian | trixie | undetermined | |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| 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 |
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
- https://security-tracker.debian.org/tracker/CVE-2026-27942
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.