> CVE-2026-55107 [CRITICAL]

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PUBLISHED
2026-09-30 18:18
MODIFIED
2026-09-30 18:18
CVSS_SCORE V3
10.0
EPSS (Prob. Exploit)
0.80%
Top 44.2%
DATA SOURCES:
NVD đź”— 2026-09-30 CWE MITRE đź”— 2026-10-01 FIRST EPSS đź”— 2026-10-20 GITHUB đź”— 2026-10-15 OSV đź”— 2026-10-07

> DESCRIPTION

Kobako is a Ruby gem that embeds a Wasm-isolated mruby interpreter inside applications, allowing execution of untrusted Ruby scripts (LLM-generated code, user formulas, student submissions, third-party plugins) in-process without giving them access to host memory, files, network, or credentials. From version 0.1.0 to before version 0.9.1, a guest mruby script running inside the Kobako sandbox can execute arbitrary Ruby in the host process, fully escaping the sandbox. This issue has been patched in version 0.9.1.

> 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:C/C:H/I:H/A:H
EXPLOITABILITY
3.9
IMPACT
6.0

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
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
Changed (C)
Impact s'Ă©tend au-delĂ  du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-94 CWE-470

> CWE DETAILED DESCRIPTIONS

CWE-94: Improper Control of Generation of Code ('Code Injection') - The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. | CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') - The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.

> GITHUB SECURITY ADVISORY

GHSA-7pwq-q9jf-539h CRITICAL

kobako Sandbox Escape: guest eval reaches host RCE via method_missing → public_send (any bound Service)

AFFECTED PACKAGES:
RUBYGEMS / kobako
>= 0.1.0, <= 0.9.0
Fixed in: 0.9.1

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Kobako Vulnerable to Sandbox Escape: guest eval reaches host RCE via method_missing → public_send (any bound Service)

AFFECTED PACKAGES:
Unknown / Unknown
22 versions affected
ALIASES:
GHSA-7pwq-q9jf-539h

> HISTORIQUE DES MODIFICATIONS

Première apparition
30/09/2026 18:18
Source: NVD
đź“Š ENRICHISSEMENT 01/10/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-94: Improper Control of Generation of Code ('Code Injection') - The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not n...
Total des modifications: 1 Dernière mise à jour: 2 weeks ago

> REFERENCES

https://github.com/elct9620/kobako/commit/64f84700c81f44902bed9211318d5362f44987...
https://github.com/elct9620/kobako/releases/tag/v0.9.1
https://github.com/elct9620/kobako/security/advisories/GHSA-7pwq-q9jf-539h
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