# CVE-2018-12121: Denial of service in Node.js

> Attackers can cause Node.js HTTP servers to crash via heap allocation failure by sending large, timed HTTP headers.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Nov 2018
- **Updated:** 8 Oct 2026
- **Also known as:** ALPINE-CVE-2018-12121, CLEANSTART-2026-RU92085, CLEANSTART-2026-ZB96802, DEBIAN-CVE-2018-12121, GHSA-2p2c-vwq7-7vg6, RHSA-2019:3497, UBUNTU-CVE-2018-12121

## What is CVE-2018-12121?

CVE-2018-12121 is a high-severity denial of service vulnerability in Nodejs Node.js, published on 28 Nov 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2018-12121?

It affects 8 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `http-parser` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.8.0-5.el8 |
| `http-parser-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.8.0-5.el8 |
| `http-parser-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.8.0-5.el8 |

Products: Nodejs Node.js, Redhat Enterprise Linux, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Tus, Redhat Enterprise Linux Workstation.

## How do I fix CVE-2018-12121?

Upgrade to a fixed version.

## Is CVE-2018-12121 being exploited?

There is no known exploitation of CVE-2018-12121 in the wild and no public exploit code.

## Other vulnerabilities in Nodejs Node.js

- [CVE-2023-32002](https://insights.sbomify.com/CVE-2023-32002/): Security feature bypass in Node (critical 9.8)
- [CVE-2016-6303](https://insights.sbomify.com/CVE-2016-6303/): Integer overflow in n/a (critical 9.8)
- [CVE-2017-15896](https://insights.sbomify.com/CVE-2017-15896/): Security feature bypass in Node.js (critical 9.1)
- [CVE-2018-7160](https://insights.sbomify.com/CVE-2018-7160/): Server-side request forgery in Node.js (high 8.8)
- [CVE-2018-12120](https://insights.sbomify.com/CVE-2018-12120/): Misconfiguration in Node.js (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-12121 and fix it if it is affected.

What it is: CVE-2018-12121 is a high-severity denial of service vulnerability in Nodejs Node.js, published on 28 Nov 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-12121 in the wild and no public exploit code.

Affected product: Nodejs Node.js. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-12121/ (Markdown: https://insights.sbomify.com/CVE-2018-12121/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-12121
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-12121
- OSV: https://osv.dev/vulnerability/CVE-2018-12121

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-12121/
Summaries are generated and may contain mistakes; the official description above is the record.