CVE-2026-25128
High
Description
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductNaturalintelligence Fast-xml-parser
PublishedJan 30, 2026
First seenJan 30, 2026
Weakness typeCWE-20Improper input validationCWE-248CWE-248
How to fix
Update
- naturalintelligence fast-xml-parser5.3.4 or later
- fast-xml-parser5.3.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| naturalintelligence fast-xml-parser | 5.0.9 ≤ v < 5.3.4 | 5.3.4 |
| fast-xml-parsernpm | 5.0.9 ≤ v < 5.3.4 | 5.3.4 |
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