# CVE-2018-1333: DoS for HTTP/2 connections by crafted requests

> Attackers can cause denial of service in Apache HTTP Server by sending crafted HTTP/2 requests that exhaust worker resources.

- **Severity:** High 7.5 (`CVSS:3.0/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:** 18 Jun 2018
- **Updated:** 17 Sep 2024
- **Also known as:** ALPINE-CVE-2018-1333, CLEANSTART-2026-MY08631, DEBIAN-CVE-2018-1333, GHSA-885g-r558-qx2m, SUSE-SU-2018:2336-1, UBUNTU-CVE-2018-1333

## What is CVE-2018-1333?

CVE-2018-1333 is a high-severity denial of service vulnerability in Apache Http Server, published on 18 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

By specially crafting HTTP/2 requests, workers would be allocated 60 seconds longer than necessary, leading to worker exhaustion and a denial of service. Fixed in Apache HTTP Server 2.4.34 (Affected 2.4.18-2.4.30,2.4.33).

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2018-1333?

It affects 5 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `apache2` | SUSE:Linux Enterprise Server 12 SP3 | All versions | 2.4.23-29.21.1 |
| `apache2` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 2.4.23-29.21.1 |
| `apache2` | SUSE:Linux Enterprise Software Development Kit 12 SP3 | All versions | 2.4.23-29.21.1 |

Products: Apache Http Server, Canonical Ubuntu Linux, Netapp Cloud Backup, Netapp Storage Automation Store, Redhat Jboss Core Services.

## How do I fix CVE-2018-1333?

Upgrade to a fixed version.

## Is CVE-2018-1333 being exploited?

There is no known exploitation of CVE-2018-1333 in the wild and no public exploit code.

## Other vulnerabilities in Apache Http Server

- [CVE-2021-42013](https://insights.sbomify.com/CVE-2021-42013/): Apache HTTP Server Path Traversal (critical 9.8, exploited in the wild)
- [CVE-2024-38475](https://insights.sbomify.com/CVE-2024-38475/): Apache HTTP Server Improper Escaping of Output (critical 9.1, exploited in the wild)
- [CVE-2021-40438](https://insights.sbomify.com/CVE-2021-40438/): Apache HTTP Server-Side Request Forgery (SSRF) (critical 9.0, exploited in the wild)
- [CVE-2019-0211](https://insights.sbomify.com/CVE-2019-0211/): Apache HTTP Server Privilege Escalation (high 7.8, exploited in the wild)
- [CVE-2021-41773](https://insights.sbomify.com/CVE-2021-41773/): Apache HTTP Server Path Traversal (high 7.5, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-1333 and fix it if it is affected.

What it is: CVE-2018-1333 is a high-severity denial of service vulnerability in Apache Http Server, published on 18 Jun 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-2018-1333 in the wild and no public exploit code.

Affected product: Apache Http Server. 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-2018-1333/ (Markdown: https://insights.sbomify.com/CVE-2018-1333/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-1333
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-1333
- OSV: https://osv.dev/vulnerability/CVE-2018-1333

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-1333/
Summaries are generated and may contain mistakes; the official description above is the record.