---
cve: "CVE-2026-33993"
severity: "MEDIUM"
cvss: 6.9
epss: "58%"
vendor: "locutusjs"
kev: false
exploited: false
published: "2026-03-27 23:17:14"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T05:48:19+02:00"
---

# CVE-2026-33993

> 6.9 MEDIUM · 🧪 PoC

## Beschreibung

Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Prior to version 3.0.25, the `unserialize()` function in `locutus/php/var/unserialize` assigns deserialized keys to plain objects via bracket notation without filtering the `__proto__` key. When a PHP serialized payload contains `__proto__` as an array or object key, JavaScript's `__proto__` setter is invoked, replacing the deserialized object's prototype with attacker-controlled content. This enables property injection, for...in propagation of injected properties, and denial of service via built-in method override. This is distinct from the previously reported prototype pollution in `parse_str` (GHSA-f98m-q3hr-p5wq, GHSA-rxrv-835q-v5mh) — `unserialize` is a different function with no mitigation applied. Version 3.0.25 patches the issue.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 0d2402bdb92f9c59918114af9c8ba628f22e9152 (Commit)
- 345a6211e1e6f939f96a7090bfeff642c9fcf9e4 (Commit)

## Referenzen

- <https://github.com/locutusjs/locutus/security/advisories/GHSA-4mph-v827-f877>
- <https://github.com/locutusjs/locutus/pull/597>
- <https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4>
- <https://github.com/locutusjs/locutus/releases/tag/v3.0.25>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-33993) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_