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 4.1.3 through 5.3.5, the XML parser can be forced to do an unlimited amount of entity expansion. With a very small XML input, it’s possible to make the parser spend seconds or even minutes processing a single request, effectively freezing the application. Version 5.3.6 fixes the issue. As a workaround, avoid using DOCTYPE parsing by `processEntities: false` option.
History

Fri, 20 Feb 2026 01:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 19 Feb 2026 20:15:00 +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. In versions 4.1.3 through 5.3.5, the XML parser can be forced to do an unlimited amount of entity expansion. With a very small XML input, it’s possible to make the parser spend seconds or even minutes processing a single request, effectively freezing the application. Version 5.3.6 fixes the issue. As a workaround, avoid using DOCTYPE parsing by `processEntities: false` option.
Title fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)
Weaknesses CWE-776
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-02-19T21:21:49.452Z

Reserved: 2026-02-12T17:10:53.414Z

Link: CVE-2026-26278

cve-icon Vulnrichment

Updated: 2026-02-19T20:58:41.932Z

cve-icon NVD

Status : Received

Published: 2026-02-19T20:25:43.717

Modified: 2026-02-19T20:25:43.717

Link: CVE-2026-26278

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.