CVE-2026-27942 LOW

CVE-2026-27942: fast-xml-parser has stack overflow in XMLBuilder with preserveOrder

Vendor Naturalintelligence
Product fast-xml-parser
Weakness CWE-120
Published February 26, 2026
Last update February 26, 2026

CVSS base score

2.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

February 26, 2026 CVE published
February 26, 2026 Record updated