CVE-2026-55107
kobako Sandbox Escape - guest eval reaches host RCE via method_missing → public_send (any bound Service)
Severidad por fuente
La etiqueta propia de Trivy es CRITICAL. Crítica según GHSA, Ruby Advisory DB.
Descripción
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.
Paquetes afectados y versiones corregidas
| Fuente | Paquete | Corregido en |
|---|---|---|
| rubygems::GitHub Security Advisory RubyGems | kobako | 0.9.1 |
| rubygems::Ruby Advisory Database | kobako | >= 0.9.1 |
Referencias
- https://advisories.gitlab.com/gem/kobako/CVE-2026-55107
- https://github.com/advisories/GHSA-7pwq-q9jf-539h
- https://github.com/elct9620/kobako
- https://github.com/elct9620/kobako/blob/main/CHANGELOG.md#091-2026-06-11
- https://github.com/elct9620/kobako/commit/64f84700c81f44902bed9211318d5362f44987b3
- https://github.com/elct9620/kobako/commit/dd081665f368f7ba54e476c3ad045ee1aa8ed703
- https://github.com/elct9620/kobako/releases/tag/v0.9.1
- https://github.com/elct9620/kobako/security/advisories/GHSA-7pwq-q9jf-539h