{"id":"CVE-2026-93606","published":"2026-09-18T14:19:12.500","lastModified":"2026-09-18T18:18:31.267","description":"vm2 (npm) versions 3.12.0 and earlier contain a sandbox escape in `VM` and `NodeVM`. When an embedder exposes a host API that returns a host-realm Promise, the bridge's rejection sanitizer (hostPromiseSanitizeReject / makeSanitizedPromiseCallback / normalizeHostPromiseCallbacks in lib/bridge.js) only wraps `then`/`catch` rejection slots that hold a function, and the sandbox-side `Symbol.species`/`.then` neutralization is installed only on the sandbox intrinsic `Promise.prototype`, so it never applies to a host Promise. Code running inside the sandbox can overwrite `p.constructor[Symbol.species]` on the host Promise and then call `p.then()` with no `onRejected` handler; V8 substitutes its internal Thrower, which re-throws the raw host rejection value into a resolve/reject closure captured by the attacker. This delivers an unsanitized, fully functional bridge proxy of the host object to sandboxed code, bypassing handleException and hostPromiseSanitizeReject. If the rejection value is host-pivotable (for example a host `process` object), this results in arbitrary code execution on the host. Fixed in 3.12.1.","cvssScore":10,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","cwes":["CWE-693"],"vendors":[],"products":[],"references":[{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-6454-5x88-m6jw","tags":[]},{"url":"https://www.vulncheck.com/advisories/vm2-before-3.12.1-sandbox-escape-via-promise-symbol-species","tags":[]},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-6454-5x88-m6jw","tags":[]}],"exploitRefs":[{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-6454-5x88-m6jw","tags":[]},{"url":"https://github.com/patriksimek/vm2/security/advisories/GHSA-6454-5x88-m6jw","tags":[]}],"hasPoc":true,"ai":{"summary":"This flaw allows code running inside the sandbox to overwrite the `Symbol.species` property of a host Promise, leading to arbitrary code execution on the host. It matters because it bypasses security measures intended to prevent such attacks.","exploitability":"Exploitation requires the embedder to expose a host API that returns a host-realm Promise. The attacker must then overwrite the `Symbol.species` property and call `then()` without an `onRejected` handler.","blast_radius":"If exploited, this flaw could result in full control over the host system, as the attacker can execute arbitrary code with the privileges of the host process.","remediation":"Upgrade to vm2 version 3.12.1 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["rce","web","vm2"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-27T08:55:09.099Z"}}