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. From 4.1.3to before 5.3.5, a dot (.) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (<, >, &, ", ') with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-m7jm-9gc2-mpf2 fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Mon, 23 Feb 2026 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 23 Feb 2026 15:00:00 +0000

Type Values Removed Values Added
First Time appeared Naturalintelligence
Naturalintelligence fast-xml-parser
Vendors & Products Naturalintelligence
Naturalintelligence fast-xml-parser

Sat, 21 Feb 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-79
References
Metrics threat_severity

None

threat_severity

Important


Fri, 20 Feb 2026 21:15:00 +0000

Type Values Removed Values Added
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. From 4.1.3to before 5.3.5, a dot (.) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (<, >, &, ", ') with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.
Title fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names
Weaknesses CWE-185
References
Metrics cvssV3_1

{'score': 9.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-02-23T19:29:10.187Z

Reserved: 2026-02-06T21:08:39.130Z

Link: CVE-2026-25896

cve-icon Vulnrichment

Updated: 2026-02-23T19:27:50.880Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-02-20T21:19:27.470

Modified: 2026-02-23T18:14:13.887

Link: CVE-2026-25896

cve-icon Redhat

Severity : Important

Publid Date: 2026-02-20T20:57:48Z

Links: CVE-2026-25896 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-02-23T14:35:10Z

Weaknesses