CVE-2026-27942

HIGH

fast-xml-parser < 5.3.8 - Denial of Service via XML Builder with preserveOrder:true

Title source: llm

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. Prior to version 5.3.8, the application crashes with stack overflow when user use XML builder with `preserveOrder:true`. Version 5.3.8 fixes the issue. As a workaround, use XML builder with `preserveOrder:false` or check the input data before passing to builder.

References (3)

Core 3

Core References

Vendor Advisory x_refsource_confirm

https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-fj3w-jwp8-x2g3

Issue Tracking x_refsource_misc

https://github.com/NaturalIntelligence/fast-xml-parser/pull/791

Patch x_refsource_misc

https://github.com/NaturalIntelligence/fast-xml-parser/commit/c13a961910f14986295dd28484eee830fa1a0e8a

View Patch ZIP pw:eip

Scores

CVSS v3 7.5

EPSS 0.0045

EPSS Percentile 35.7%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact partial

Details

CWE

CWE-120

Status published

Products (3)

fast-xml-parser_project/fast-xml-parser < 4.5.4

naturalintelligence/fast-xml-parser < 4.5.4

npm/fast-xml-parser 0 - 5.3.8npm

Published Feb 26, 2026

Tracked Since Feb 26, 2026