Buffer Overflow Affecting fast-xml-parser package, versions <4.5.4>=5.0.0 <5.3.8
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-FASTXMLPARSER-15353391
- published26 Feb 2026
- disclosed26 Feb 2026
- creditUnknown
Introduced: 26 Feb 2026
NewCVE-2026-27942 (opens in a new tab)How to fix?
Upgrade fast-xml-parser to version 4.5.4, 5.3.8 or higher.
Overview
fast-xml-parser is a Validate XML, Parse XML, Build XML without C/C++ based libraries
Affected versions of this package are vulnerable to Buffer Overflow via the XMLBuilder when preserveOrder:true is set. An attacker can cause the application to crash by providing specially crafted input data.
Workaround
This vulnerability can be mitigated by using preserveOrder:false or by validating input data before passing it to the builder.