> CVE-2026-33993 [MEDIUM]

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PUBLISHED
2026-03-27 23:17
MODIFIED
2026-03-27 23:17
CVSS_SCORE V3
6.9
EPSS (Prob. Exploit)
0.59%
Top 51.5%
DATA SOURCES:
NVD đź”— 2026-03-28 CWE MITRE đź”— 2026-11-01 FIRST EPSS đź”— 2026-11-08 GITHUB đź”— 2026-11-05 OSV đź”— 2026-11-01

> DESCRIPTION

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.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

> MÉTRIQUES CVSS DÉTAILLÉES

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
None (N)
Aucune divulgation d'informations
I (Impact Intégrité)
Integrity Impact
Low (L)
Modification limitée des données possible
A (Impact Disponibilité)
Availability Impact
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

Confidentialité
None
Aucune divulgation d'informations
Intégrité
Low
Modification limitée des données possible
Disponibilité
None
Aucune interruption de service

> WEAKNESSES

CWE-1321

> CWE DETAILED DESCRIPTIONS

CWE-1321: Improperly Controlled Modification of Object Prototype Attributes - The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

> GITHUB SECURITY ADVISORY

GHSA-4mph-v827-f877 MODERATE

Locutus has Prototype Pollution via __proto__ Key Injection in unserialize()

AFFECTED PACKAGES:
NPM / locutus
< 3.0.25
Fixed in: 3.0.25

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Locutus has Prototype Pollution via __proto__ Key Injection in unserialize()

AFFECTED PACKAGES:
Unknown / Unknown
64 versions affected
ALIASES:
GHSA-4mph-v827-f877

> HISTORIQUE DES MODIFICATIONS

Première apparition
27/03/2026 23:17
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') - The product receives input from an upstream component that specifies attributes that are to be ini...
Nouvelle valeur:
CWE-1321: Improperly Controlled Modification of Object Prototype Attributes - The product receives input from an upstream component that specifies attributes that are to be initialized or updated in a...
📊 ENRICHISSEMENT 01/04/2026 06:02
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') - The product receives input from an upstream component that specifies attributes that are to be ini...
Total des modifications: 2 Dernière mise à jour: 1 week ago

> REFERENCES

https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fc...
https://github.com/locutusjs/locutus/pull/597
https://github.com/locutusjs/locutus/releases/tag/v3.0.25
https://github.com/locutusjs/locutus/security/advisories/GHSA-4mph-v827-f877
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