CVE-2026-27942
February 26, 2026
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.
Affected Packages
https://github.com/NaturalIntelligence/fast-xml-parser.git (GITHUB):
Affected version(s) >=v5.0.0 <v5.3.8Fix Suggestion:
Update to version v5.3.8fast-xml-parser (NPM):
Affected version(s) >=4.0.0-beta.0 <4.5.4Fix Suggestion:
Update to version 4.5.4fast-xml-parser (NPM):
Affected version(s) >=5.0.0 <5.3.8Fix Suggestion:
Update to version 5.3.8Related Resources (5)
Do you need more information?
Contact UsCVSS v4
Base Score:
2.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
Exploit Maturity
UNREPORTED
CVSS v3
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Weakness Type (CWE)
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
EPSS
Base Score:
0.05
