{"id":"CVE-2026-23830","summary":"SandboxJS has Sandbox Escape via Unprotected AsyncFunction Constructor","details":"SandboxJS is a JavaScript sandboxing library. Versions prior to 0.8.26 have a sandbox escape vulnerability due to `AsyncFunction` not being isolated in `SandboxFunction`. The library attempts to sandbox code execution by replacing the global `Function` constructor with a safe, sandboxed version (`SandboxFunction`). This is handled in `utils.ts` by mapping `Function` to `sandboxFunction` within a map used for lookups. However, before version 0.8.26, the library did not include mappings for `AsyncFunction`, `GeneratorFunction`, and `AsyncGeneratorFunction`. These constructors are not global properties but can be accessed via the `.constructor` property of an instance (e.g., `(async () =\u003e {}).constructor`). In `executor.ts`, property access is handled. When code running inside the sandbox accesses `.constructor` on an async function (which the sandbox allows creating), the `executor` retrieves the property value. Since `AsyncFunction` was not in the safe-replacement map, the `executor` returns the actual native host `AsyncFunction` constructor. Constructors for functions in JavaScript (like `Function`, `AsyncFunction`) create functions that execute in the global scope. By obtaining the host `AsyncFunction` constructor, an attacker can create a new async function that executes entirely outside the sandbox context, bypassing all restrictions and gaining full access to the host environment (Remote Code Execution). Version 0.8.26 patches this vulnerability.","aliases":["GHSA-wxhw-j4hc-fmq6"],"modified":"2026-08-12T03:51:13.238525025Z","published":"2026-01-27T23:32:16.104Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-693","CWE-913","CWE-94"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23830.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23830.json"},{"type":"ADVISORY","url":"https://github.com/nyariv/SandboxJS/security/advisories/GHSA-wxhw-j4hc-fmq6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23830"},{"type":"FIX","url":"https://github.com/nyariv/SandboxJS/commit/345aee6566e47979dee5c337b925b141e7f78ccd"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nyariv/sandboxjs","events":[{"introduced":"0"},{"fixed":"354229c64992478dc43ca9345543b5fed83ccf66"},{"fixed":"345aee6566e47979dee5c337b925b141e7f78ccd"}],"database_specific":{"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:nyariv:sandboxjs:*:*:*:*:*:node.js:*:*","extracted_events":[{"introduced":"0"},{"fixed":"0.8.26"}]}}],"versions":["0.8.24-2","0.8.24-1","0.8.24","0.8.23.3","0.8.23-1","0.8.23.2","0.8.23","0.8.22","0.8.21","0.8.20","0.8.19","0.8.18","0.8.17","0.8.16","0.8.15.1","0.8.15","0.8.14","0.8.12","0.8.11","0.8.10","0.8.9","0.8.8","0.8.7","0.8.6","0.8.5","0.8.4","0.8.3","0.8.2","0.8.0","0.7.1","0.7.0","0.6.2","0.6.1","0.6.0","0.5.3","0.5.2","0.5.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23830.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"}]}