vm2 through 3.12.0 (fixed in 3.12.1) does not correctly handle a nullish `this` receiver in the apply trap of its bridge (lib/bridge.js): when sandboxed code calls a host-provided non-strict (sloppy-mode) function without a receiver — e.g. `fn()`, a detached method, `fn.call()`, `fn.apply(undefined)`, `Reflect.apply(fn, undefined, [])`, or `fn.bind()()` — the undefined receiver is passed straight through to the host call, and V8 substitutes the host realm's global object for `this`. vm2 then wraps and returns that object to the sandbox, giving sandboxed script a live proxy of the host global. This allows a complete sandbox escape: untrusted script can reach `process` and execute arbitrary code/commands on the host (for example via `process.getBuiltinModule('child_process').execSync`). Exploitation requires that the embedding application expose at least one non-strict host function to the sandbox; strict-mode and ES module host functions are not affected.
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History
Fri, 18 Sep 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | vm2 through 3.12.0 (fixed in 3.12.1) does not correctly handle a nullish `this` receiver in the apply trap of its bridge (lib/bridge.js): when sandboxed code calls a host-provided non-strict (sloppy-mode) function without a receiver — e.g. `fn()`, a detached method, `fn.call()`, `fn.apply(undefined)`, `Reflect.apply(fn, undefined, [])`, or `fn.bind()()` — the undefined receiver is passed straight through to the host call, and V8 substitutes the host realm's global object for `this`. vm2 then wraps and returns that object to the sandbox, giving sandboxed script a live proxy of the host global. This allows a complete sandbox escape: untrusted script can reach `process` and execute arbitrary code/commands on the host (for example via `process.getBuiltinModule('child_process').execSync`). Exploitation requires that the embedding application expose at least one non-strict host function to the sandbox; strict-mode and ES module host functions are not affected. | |
| Title | vm2 before 3.12.1 Sandbox Escape RCE via Non-Strict Host Function | |
| First Time appeared |
Vm2 Project
Vm2 Project vm2 |
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| Weaknesses | CWE-94 | |
| CPEs | cpe:2.3:a:vm2_project:vm2:*:*:*:*:*:node.js:*:* | |
| Vendors & Products |
Vm2 Project
Vm2 Project vm2 |
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| References |
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| Metrics |
cvssV3_1
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MITRE
Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-09-18T13:20:12.955Z
Reserved: 2026-09-18T11:00:32.756Z
Link: CVE-2026-93603
Vulnrichment
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NVD
Status : Deferred
Published: 2026-09-18T14:19:12.003
Modified: 2026-09-18T14:19:12.123
Link: CVE-2026-93603
Redhat
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OpenCVE Enrichment
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Weaknesses