CVE-2026-25128

fast-xml-parser has RangeError DoS Numeric Entities Bug

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

NaturalIntelligence · fast-xml-parser

CVSS v3.1 GITHUB

7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.62% chance of exploitation in the next 30 days, 49th percentile

Published

2026-01-30

Updated

2026-02-11

Proof-of-concept exploits (1)

• advisories/GHSA-37qj-frw5-hhjh

Security advisories

• NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-37qj-frw5-hhjh
• NaturalIntelligence/fast-xml-parser/commit/4e387f61c4a5cef792f6a2f42467013290bf95dc

References

• CVE Record
• NVD entry