vm2: NodeVM observability builtins leak host process and HTTP request data

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 version 3.11.4, NodeVM exposes some process-wide observability builtins when they are allowed through require.builtin. The diagnostics_channel, async_hooks, and perf_hooks builtins are not blocked by the dangerous builtin denylist. These modules are process-wide, not sandbox-local. Sandboxed code can use them to observe host application data across the vm2 boundary. This issue has been patched in version 3.11.4.

Source published

12 Jun 2026 14:17:35 UTC

Source modified

13 Jun 2026 03:10:24 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, NodeVM exposes some process-wide observability builtins when they are allowed through require.builtin. The diagnostics_channel, async_hooks, and perf_hooks builtins are not blocked by the dangerous builtin denylist. These modules are process-wide, not sandbox-local. Sandboxed code can use them to observe host application data across the vm2 boundary. This issue has been patched in version 3.11.4.

Source published

Jun 12, 2026, 2:17:35 PM (timezone not stated)

Source modified

Jun 13, 2026, 3:10:24 AM (timezone not stated)

Observed here

7 Nov 2026 10:39:53 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 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

vm2 is an open source vm/sandbox for Node.js. Prior to version 3.11.4, NodeVM exposes some process-wide observability builtins when they are allowed through require.builtin. The diagnostics_channel, async_hooks, and perf_hooks builtins are not blocked by the dangerous builtin denylist. These modules are process-wide, not sandbox-local. Sandboxed code can use them to observe host application data across the vm2 boundary. This issue has been patched in version 3.11.4.

Source published

12 Jun 2026 15:16:28 UTC

Source modified

26 Oct 2026 11:10:00 UTC

Observed here

27 Oct 2026 13:11:40 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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

## Summary `NodeVM` exposes some process-wide observability builtins when they are allowed through `require.builtin`. The following builtins are not blocked by the dangerous builtin denylist: ```text diagnostics_channel async_hooks perf_hooks ``` These modules are process-wide, not sandbox-local. Sandboxed code can use them to observe host application data across the vm2 boundary. **Note**: It is a host data exposure issue. The impact depends on whether the host application allows these builtins and uses HTTP, async request context, diagnostics channels, or performance marks in the same process. ## Details Non-denied builtins are exposed to the sandbox through `lib/builtin.js`: ```js builtins.set(key, special ? special : vm => vm.readonly(hostRequire(key))); ``` `diagnostics_channel`, `async_hooks`, and `perf_hooks` are not denied. These modules expose host process state rather than sandbox-local state. Confirmed examples: 1. `diagnostics_channel` lets sandboxed code subscribe to Node.js HTTP diagnostic channels such as `http.server.request.start`. The sandbox receives host HTTP request objects and can read headers such as `Authorization` or session tokens. 2. `async_hooks.executionAsyncResource()` lets sandboxed code read the current host `AsyncResource`. If the host stores request/user data on that resource, the sandbox can read it. 3. `perf_hooks.performance.getEntriesByType('mark')` lets sandboxed code read host performance timeline entries. ## PoC Run from the vm2 repository root: ```bash node poc/observability-builtins-info-leak.js ``` [observability-builtins-info-leak.js](https://github.com/user-attachments/files/27571259/observability-builtins-info-leak.js) The PoC uses only the specific builtin being tested in each section. It confirms: ```text diagnostics_channel: sandbox reads host HTTP request headers async_hooks: sandbox reads host AsyncResource data perf_hooks: sandbox reads host performance mark names ``` Example impact from the PoC: ```text authorization: Bearer HOST_HTTP_SECRET_... x-session-token: HOST_HTTP_SECRET_... ``` These values are sent to a host HTTP server, but the sandbox reads them through `diagnostics_channel`. <img width="997" height="566" alt="Screenshot 2026-05-10 at 1 13 20 PM" src="https://github.com/user-attachments/assets/36a7d600-8b53-4bfe-ab06-4e6dcfad5015" /> ## Impact An attacker who can run untrusted JavaScript inside `NodeVM` with affected builtin settings can observe data from the host process. In a real application, this may expose HTTP request headers, authorization tokens, session tokens, request context values, user identifiers, or other sensitive diagnostics data from the host application or from other users. ## Suggested fix Treat process-wide observability modules as dangerous builtins for untrusted sandboxes. At minimum, consider blocking: ```text diagnostics_channel async_hooks perf_hooks ``` These modules are not sandbox-local and can expose host process state across the vm2 boundary.

Source published

29 May 2026 18:20:45 UTC

Source modified

12 Jun 2026 19:45:09 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_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N/E:U

Publisher rating · MODERATE