# CVE-2018-6347: Denial of service in Proxygen

> Attackers can cause a denial of service in applications using the Proxygen library by sending malformed HTTP2 headers or trailers.

- **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:** No
- **Published:** 31 Dec 2018
- **Updated:** 6 May 2025
- **Also known as:** GHSA-95px-qh9x-29gf

## What is CVE-2018-6347?

CVE-2018-6347 is a high-severity denial of service vulnerability in Facebook Proxygen, published on 31 Dec 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue in the Proxygen handling of HTTP2 parsing of headers/trailers can lead to a denial-of-service attack. This affects Proxygen prior to v2018.12.31.00.

Weakness: CWE-20 (Improper Input Validation), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2018-6347?

It affects 1 product.


Products: Proxygen Project Proxygen.

## How do I fix CVE-2018-6347?

No fix has been published for CVE-2018-6347 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-6347 being exploited?

There is no known exploitation of CVE-2018-6347 in the wild and no public exploit code.

## Other vulnerabilities in Facebook Proxygen

- [CVE-2015-7264](https://insights.sbomify.com/CVE-2015-7264/): Other in Facebook Proxygen before 2015-11-09 (critical 9.8)
- [CVE-2018-6346](https://insights.sbomify.com/CVE-2018-6346/): Denial of service in Proxygen (high 7.5)
- [CVE-2015-7263](https://insights.sbomify.com/CVE-2015-7263/): Security feature bypass in Facebook Proxygen before 2015-11-09 (high 7.5)
- [CVE-2015-7265](https://insights.sbomify.com/CVE-2015-7265/): Security feature bypass in Facebook Proxygen before 2015-11-09 (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-6347 and fix it if it is affected.

What it is: CVE-2018-6347 is a high-severity denial of service vulnerability in Facebook Proxygen, published on 31 Dec 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-2018-6347 in the wild and no public exploit code.

Affected product: Facebook Proxygen. 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-2018-6347/ (Markdown: https://insights.sbomify.com/CVE-2018-6347/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-6347
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-6347
- OSV: https://osv.dev/vulnerability/CVE-2018-6347

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-6347/
Summaries are generated and may contain mistakes; the official description above is the record.