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CVE-2026-33036
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2026-03-20T06:16:11.630 · Last modified 2026-06-17T10:36:50.727

Summary

fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Versions 4.0.0-beta.3 through 5.5.5 contain a bypass vulnerability where numeric character references (&#NNN;, &#xHH;) and standard XML entities completely evade the entity expansion limits (e.g., maxTotalExpansions, maxExpandedLength) added to fix CVE-2026-26278, enabling XML entity expansion Denial of Service. The root cause is that replaceEntitiesValue() in OrderedObjParser.js only enforces expansion counting on DOCTYPE-defined entities while the lastEntities loop handling numeric/standard entities performs no counting at all. An attacker supplying 1M numeric entity references like A can force ~147MB of memory allocation and heavy CPU usage, potentially crashing the process—even wh

Affected products

naturalintelligence — fast-xml-parser

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.