Description
The fix for CVE-2026-26278 added entity expansion limits (maxTotalExpansions, maxExpandedLength, maxEntityCount, maxEntitySize) to prevent XML entity expansion Denial of Service. However, these limits are only enforced for DOCTYPE-defined entities.
Recommendation
Update the fast-xml-parser package to the latest compatible version. Followings are version details:
Affected version(s): **>= 4.0.0-beta.3, < 4.5.5 >= 5.0.0, < 5.5.6** Patched version(s): **4.5.5 5.5.6**
References
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Start a free scanRelated Issues
- Entity Expansion Limits Bypassed When Set to Zero Due to JavaScript Falsy Evaluation in fast-xml-parser - CVE-2026-33349
- fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit) - CVE-2026-26278
- fast-xml-parser: Repeated DOCTYPE declarations reset entity expansion limits - CVE-2026-73569
- fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names - CVE-2026-25896
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See something that needs correcting? Let us knowUpdated March 25, 2026