CVE-2026-25128
January 30, 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. In versions 5.0.9 through 5.3.3, a RangeError vulnerability exists in the numeric entity processing of fast-xml-parser when parsing XML with out-of-range entity code points (e.g., "�" or "�"). This causes the parser to throw an uncaught exception, crashing any application that processes untrusted XML input. Version 5.3.4 fixes the issue.
Affected Packages
https://github.com/NaturalIntelligence/fast-xml-parser.git (GITHUB):
Affected version(s) >=v4.3.6 <v5.3.4Fix Suggestion:
Update to version v5.3.4fast-xml-parser (NPM):
Affected version(s) >=5.0.9 <5.3.4Fix Suggestion:
Update to version 5.3.4Related Resources (5)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
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
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
EPSS
Base Score:
0.05
