# CVE-2020-8192: Denial of service in fastify

> Attackers can cause resource exhaustion and denial of service in Fastify applications using the allErrors option via crafted schemas.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Jul 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-xw5p-hw6r-2j98

## What is CVE-2020-8192?

CVE-2020-8192 is a medium-severity denial of service vulnerability in fastify, published on 30 Jul 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A denial of service vulnerability exists in Fastify v2.14.1 and v3.0.0-rc.4 that allows a malicious user to trigger resource exhaustion (when the allErrors option is used) with specially crafted schemas.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2020-8192?

2 open source packages ship an affected version, including fastify. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `fastify` | npm | All versions | 2.15.1 |
| `fastify` | npm | All versions | 2.15.1 |

Products: Fastify Fastify.

## How do I fix CVE-2020-8192?

Upgrade fastify to 2.15.1 or later.

## Is CVE-2020-8192 being exploited?

There is no known exploitation of CVE-2020-8192 in the wild and no public exploit code.

## Other vulnerabilities in fastify

- [CVE-2026-84504](https://insights.sbomify.com/CVE-2026-84504/): fastify vulnerable to request body replacement via an async validation result collision (high 8.1)
- [CVE-2026-76169](https://insights.sbomify.com/CVE-2026-76169/): fastify vulnerable to authentication bypass via malformed URLs reaching encapsulated not-found handlers (high 7.5)
- [CVE-2026-84428](https://insights.sbomify.com/CVE-2026-84428/): fastify vulnerable to header validation bypass via incomplete schema case normalization (high 7.5)
- [CVE-2026-84469](https://insights.sbomify.com/CVE-2026-84469/): fastify vulnerable to request validation bypass via skipped boolean false schemas (high 7.5)
- [CVE-2026-33806](https://insights.sbomify.com/CVE-2026-33806/): fastify vulnerable to Body Schema Validation Bypass via Leading Space in Content-Type Header (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8192 and fix it if it is affected.

What it is: CVE-2020-8192 is a medium-severity denial of service vulnerability in fastify, published on 30 Jul 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-8192 in the wild and no public exploit code.

Affected packages and fixed versions:
- fastify (npm): affected all versions; fixed in 2.15.1
- fastify (npm): affected all versions; fixed in 2.15.1

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-2020-8192/ (Markdown: https://insights.sbomify.com/CVE-2020-8192/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8192
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8192
- OSV: https://osv.dev/vulnerability/CVE-2020-8192

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8192/
Summaries are generated and may contain mistakes; the official description above is the record.