vm2: Improper Control of Generation of Code
CVE-2026-92937 is a critical-severity improper control of generation of code vulnerability in vm2 from Patriksimek, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 3.11.7 as the first without the flaw, so updating vm2 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.03% chance of exploitation within 30 days, higher than 64% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update vm2 to 3.11.7 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Patriksimek | vm2 | 3.11.6 up to, but not including, 3.11.7 | 3.11.7 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 10.0 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 10.0 | Critical | CNA (vulncheck.com) |
Official description
vm2 3.11.6 is vulnerable to a sandbox escape leading to remote code execution in the host Node.js process. The fix for GHSA-m283-3h24-438v is incomplete: the bridge gate at lib/bridge.js:1624 identity-checks only the direct call target when deciding whether to rebuild/sanitise a rejected host Promise value. Registering the rejection handler through Function.prototype.call or .apply indirection (e.g., p.then.call(p, undefined, cb)) makes the intercepted target host Function.prototype.call, so the sanitiser never runs and the raw host error reaches sandbox code with its own properties intact. If an embedder exposes a host-realm Promise to the sandbox (an async host function bridged via the sandbox option, or a NodeVM external module's async method) and that Promise rejects with an Error carrying a non-primitive own property referencing a host object (for example err.detail = process), untrusted code in the sandbox obtains a fully functional proxy to that host object and can execute arbitrary commands with the privileges of the host process (e.g., e.detail.mainModule.require('child_process').execSync(...)). The direct p.then(undefined, cb), bind, and Reflect.apply forms are correctly sanitised. Fixed in vm2 3.11.7.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Control of Generation of Code
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
How developers prevent this class of flaw
- Refactor your program so that you do not have to dynamically generate code.
- Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
More Improper Control of Generation of Code vulnerabilities (CWE-94)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in vm2
- 7.5 High severity
- 9.0 Critical severity
- 10.0 Critical severity
- 10.0 Critical severity
- 7.2 High severity
- 10.0 Critical severity
Recent Improper Control of Generation of Code vulnerabilities
- 9.3 Critical severity
- 9.0 Critical severity
- 7.8 High severity
- 9.0 Critical severity
- 8.8 High severity
- 7.5 High severity
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