---
cve: "CVE-2026-26278"
severity: "HIGH"
cvss: 7.5
epss: "0.9%"
vendor: "NaturalIntelligence"
kev: false
exploited: false
published: "2026-02-19 20:25:43"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-24T07:12:22+02:00"
---

# CVE-2026-26278

> 7.5 HIGH · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- ecb2ca118ad3d6c62f2cc90416b58da24db5d18b (Commit)
- 910dae5be2de2955e968558fadf6e8f74f117a77 (Commit)

## Referenzen

- <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/errata/RHSA-2026:40984>
- <https://access.redhat.com/errata/RHSA-2026:41941>
- <https://access.redhat.com/errata/RHSA-2026:41944>
- <https://access.redhat.com/errata/RHSA-2026:51349>
- <https://access.redhat.com/errata/RHSA-2026:6174>
- <https://access.redhat.com/errata/RHSA-2026:6802>
- <https://access.redhat.com/errata/RHSA-2026:7110>
- <https://access.redhat.com/errata/RHSA-2026:7128>
- <https://access.redhat.com/security/cve/CVE-2026-26278>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-26278) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_