> CVE-2026-55091 [HIGH]

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PUBLISHED
2026-09-14 18:17
MODIFIED
2026-09-14 18:17
CVSS_SCORE V3
7.5
EPSS (Prob. Exploit)
0.50%
Top 58.7%
DATA SOURCES:
NVD đź”— 2026-09-14 CWE MITRE đź”— 2026-10-01 FIRST EPSS đź”— 2026-10-18 GITHUB đź”— 2026-09-21 OSV đź”— 2026-10-26

> DESCRIPTION

flat-to-nested converts a hierarchy from a flat representation to a nested representation. Prior to 1.1.2, FlatToNested.prototype.convert in index.js uses attacker-influenced id and parent record fields directly as keys in the plain temp and pendingChildOf objects. When parent or id is __proto__, temp[parent] can resolve to Object.prototype, and initPush() can write attacker-controlled data to the global children prototype property while existing prototype methods remain intact. Any application that passes attacker-influenced flat records to convert() can therefore expose unrelated objects to polluted inherited state, causing application-logic corruption or denial of service and potentially enabling greater impact when a downstream prototype-pollution gadget is present. The constructor and prototype strings are also unsafe inherited-key values in the same lookup design. This issue is fixed in version 1.1.2.

> AFFECTED_PRODUCTS

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

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EXPLOITABILITY
3.9
IMPACT
3.6

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

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

> WEAKNESSES

CWE-915 CWE-1321

> CWE DETAILED DESCRIPTIONS

CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes - The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified. | 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 initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

> GITHUB SECURITY ADVISORY

GHSA-hp36-v28f-w3r4 HIGH

flat-to-nested: Prototype pollution in flat-to-nested convert() via __proto__ parent/id key

AFFECTED PACKAGES:
NPM / flat-to-nested
<= 1.1.1
Fixed in: 1.1.2

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

flat-to-nested: Prototype pollution in flat-to-nested convert() via __proto__ parent/id key

AFFECTED PACKAGES:
Unknown / Unknown
5 versions affected
ALIASES:
GHSA-hp36-v28f-w3r4

> HISTORIQUE DES MODIFICATIONS

Première apparition
14/09/2026 18:17
Source: NVD
📊 ENRICHISSEMENT 01/10/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes - The product receives input from an upstream component that specifies multiple attributes, properties, or field...
Total des modifications: 1 Dernière mise à jour: 3 weeks ago

> REFERENCES

https://github.com/joaonuno/flat-to-nested-js/commit/680a5ebe1194edda16fa93baaa5...
https://github.com/joaonuno/flat-to-nested-js/releases/tag/v1.1.2
https://github.com/joaonuno/flat-to-nested-js/security/advisories/GHSA-hp36-v28f...
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