---
cve: "CVE-2026-25521"
severity: "CRITICAL"
cvss: 9.4
epss: "26%"
vendor: "locutusjs"
kev: false
exploited: false
published: "2026-02-04 22:15:59"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T07:27:05+02:00"
---

# CVE-2026-25521

> 9.4 CRITICAL · 🧪 PoC

## Beschreibung

Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. In versions from 2.0.12 to before 2.0.39, a prototype pollution vulnerability exists in locutus. Despite a previous fix that attempted to mitigate prototype pollution by checking whether user input contained a forbidden key, it is still possible to pollute Object.prototype via a crafted input using String.prototype. This issue has been patched in version 2.0.39.

## CVSS-Vektor

```
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- fb90ed0cb832897ef15880be446ab124e3313047 (Commit)
- 042af9ca7fde2ff599120783e720a17f335bb01c (Commit)

## Referenzen

- <https://github.com/locutusjs/locutus/security/advisories/GHSA-rxrv-835q-v5mh>
- <https://github.com/locutusjs/locutus/commit/042af9ca7fde2ff599120783e720a17f335bb01c>
- <https://access.redhat.com/security/cve/CVE-2026-25521>
- <https://bugzilla.redhat.com/show_bug.cgi?id=2436950>
- <https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25521.json>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-25521) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_