Buffer Overflow Affecting fast-xml-parser package, versions <4.5.4>=5.0.0 <5.3.8
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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)Common Vulnerabilities and Exposures (CVE) are common identifiers for publicly known security vulnerabilities
Common Weakness Enumeration (CWE) is a category system for software weaknesses
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.