AIKIDO-2026-10621
fast-xml-parser is vulnerable to Denial of Service (DoS)
53
Medium Risk
This Affects:
fast-xml-parserTL;DR
The XML parser's tagExpWithClosingIndex() path in src/xmlparser/OrderedObjParser.js handled tag expressions by building a large intermediate character buffer and materializing it with spread-style conversion, which can overflow stack or exhaust resources on extremely long tag expressions. Applications that parse attacker-controlled XML can be forced into excessive memory or stack usage during tag parsing, causing parse failure or process instability. The patch replaces that construction approach with segmented substring() accumulation and controlled tab normalization while scanning, reducing peak overhead for very long expressions.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range.
Background info
fast-xml-parser is vulnerable to Denial of Service (DoS) in versions 4.0.0 - 5.7.1.
How to fix this
Upgrade the fast-xml-parser library to the patch version.
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SOC 2Compliant
ISO 27001Compliant