CVE-2026-55107

Summary

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 Software

VendorProductVersion RangeStatus
elct9620kobako>= 0.1.0, < 0.9.1affected

Weaknesses

  • CWE-94: CWE-94: Improper Control of Generation of Code ('Code Injection')
  • CWE-470: CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: total

Additional References

References