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CVE-2026-55107

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

Description (CNA)

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 (CNA)

Vendor / productVersions
elct9620 / kobakoaffected >= 0.1.0, < 0.9.1

CWE

CWE-94, CWE-470

References

ADP enrichment

CISA-ADP

No English description supplied.