CVE-2026-93606

CVSS 10.0 (critical) · published 2026-09-18

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.

Weakness: CWE-693

Source: NVD CVE-2026-93606

References

• https://github.com/patriksimek/vm2/security/advisories/GHSA-6454-5x88-m6jw
• https://www.vulncheck.com/advisories/vm2-before-3.12.1-sandbox-escape-via-promise-symbol-species
• https://github.com/patriksimek/vm2/security/advisories/GHSA-6454-5x88-m6jw

Check your software

Connect an AI agent to the FixLane MCP server or ask the Telegram bot to check what you have installed against incidents with a verified fixed version.