CVE-2026-55107

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Source
https://cve.org/CVERecord?id=CVE-2026-55107
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55107.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-55107
Aliases
Published
2026-09-30T17:06:00Z
Modified
2026-10-28T02:30:36Z
Severity
  • 10.0 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H CVSS Calculator
Summary
Kobako Vulnerable to Sandbox Escape: guest eval reaches host RCE via method_missing → public_send (any bound Service)
Details

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.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-470",
        "CWE-94"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55107.json"
}
References

Affected packages

Git / github.com/elct9620/kobako

Affected ranges

Type
GIT
Repo
https://github.com/elct9620/kobako
Events
Introduced
631ddc7f04bf34b39e5eb66520e1692240f8f231
Fixed
98e854d2cff111bd7a8c7760d95b6f4cad6c4af8
Fixed
64f84700c81f44902bed9211318d5362f44987b3
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "0.1.0"
                },
                {
                    "fixed":  "0.9.1"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "fixed":  "64f84700c81f44902bed9211318d5362f44987b3"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "original_tag":  "v0.9.1",
            "range":  [
                {
                    "fixed":  "98e854d2cff111bd7a8c7760d95b6f4cad6c4af8"
                }
            ],
            "source":  "REFERENCES_TAG"
        }
    ]
}

Affected versions

kobako-core-v0.*
kobako-core-v0.2.0
kobako-core-v0.3.0
kobako-core-v0.4.0
kobako-io-v0.*
kobako-io-v0.3.0
kobako-io-v0.4.0
kobako-regexp-v0.*
kobako-regexp-v0.4.0
kobako-rs-v0.*
kobako-rs-v0.3.0
kobako-rs-v0.4.0
v0.*
v0.1.0
v0.1.1
v0.1.2
v0.2.0
v0.2.1
v0.3.0
v0.4.0
v0.5.0
v0.6.0
v0.6.1
v0.6.2
v0.7.0
v0.8.0
v0.9.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55107.json"