fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit) (NaturalIntelligence fast-xml-parser)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.94 % · percentile 61 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
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. In versions 4.1.3 through 5.3.5, the XML parser can be forced to do an unlimited amount of entity expansion. With a very small XML input, it’s possible to make the parser spend seconds or even minutes processing a single request, effectively freezing the application. Version 5.3.6 fixes the issue. As a workaround, avoid using DOCTYPE parsing by `processEntities: false` option.
Weaknesses (CWE)
- CWE-776 — Improper Restriction of Recursive Entity References in DTDs
References
- https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-jmr7-xgp7-cmfj
- https://github.com/NaturalIntelligence/fast-xml-parser/commit/910dae5be2de2955e968558fadf6e8f74f117a77
- https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.6
- https://access.redhat.com/security/cve/CVE-2026-26278
- https://bugzilla.redhat.com/show_bug.cgi?id=2441120
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26278.json
- https://access.redhat.com/errata/RHSA-2026:7110
- https://access.redhat.com/errata/RHSA-2026:7128
- https://access.redhat.com/errata/RHSA-2026:6174
- https://access.redhat.com/errata/RHSA-2026:6802
- https://access.redhat.com/errata/RHSA-2026:41941
- https://access.redhat.com/errata/RHSA-2026:41944
- https://access.redhat.com/errata/RHSA-2026:40984
- https://access.redhat.com/errata/RHSA-2026:51349
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Advisories
- GHSA-jmr7-xgp7-cmfj — fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)
European references
- ENISA EUVD · EUVD-2026-7970
- GCVE · GCVE-0-2026-26278
CERT-FR advisories
- CERTFR-2026-AVI-0667 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0523 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:naturalintelligence:fast-xml-parser:*:*:*:*:*:*:*:*≥ 4.1.3 < 5.3.6
Affected products
| Product | Versions |
|---|---|
| NaturalIntelligence · fast-xml-parser | affected >= 5.0.0, < 5.3.6 ; affected >= 4.1.3, < 4.5.4 |
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 |