fast-xml-parser: Entity Expansion Limits Bypassed When Set to Zero Due to JavaScript Falsy Evaluation (NaturalIntelligence fast-xml-parser)
En bref
- Source
- NVD
- EPSS
- EPSS 0.47 % · centile 40 ()
- État
- PUBLISHED
- Publiée
- Mise à jour
- Attribuée par
- GitHub_M
- Statut NVD
- Analyzed
Description
fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. From version 4.0.0-beta.3 to before version 5.5.7, the DocTypeReader in fast-xml-parser uses JavaScript truthy checks to evaluate maxEntityCount and maxEntitySize configuration limits. When a developer explicitly sets either limit to 0 — intending to disallow all entities or restrict entity size to zero bytes — the falsy nature of 0 in JavaScript causes the guard conditions to short-circuit, completely bypassing the limits. An attacker who can supply XML input to such an application can trigger unbounded entity expansion, leading to memory exhaustion and denial of service. This issue has been patched in version 5.5.7.
Faiblesses (CWE)
- CWE-1284 — Validation incorrecte d'une quantité spécifiée en entrée
Références
Scores
| Version | Score | Vecteur | Évalué par |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
| CVSS 3.1 | MEDIUM 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · security-advisories@github.com (Secondary) |
Avis
- GHSA-jp2q-39xq-3w4g — Entity Expansion Limits Bypassed When Set to Zero Due to JavaScript Falsy Evaluation in fast-xml-parser
Références européennes
- ENISA EUVD · EUVD-2026-20080
- GCVE · GCVE-0-2026-33349
Avis du CERT-FR
- CERTFR-2026-AVI-0667 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Configurations affectées (CPE NVD)
cpe:2.3:a:naturalintelligence:fast-xml-parser:*:*:*:*:*:*:*:*≥ 4.0.1 < 4.5.5cpe:2.3:a:naturalintelligence:fast-xml-parser:*:*:*:*:*:*:*:*≥ 5.0.0 < 5.5.7cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:-:*:*:*:*:*:*cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:beta3:*:*:*:*:*:*cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:beta4:*:*:*:*:*:*cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:beta5:*:*:*:*:*:*cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:beta6:*:*:*:*:*:*cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:beta7:*:*:*:*:*:*cpe:2.3:a:naturalintelligence:fast-xml-parser:4.0.0:beta8:*:*:*:*:*:*
Produits affectés
| Produit | Versions |
|---|---|
| NaturalIntelligence · fast-xml-parser | affected >= 4.0.0-beta.3, < 5.5.7 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |