# CVE-2021-42219: Denial of service in go-ethereum

> Attackers can cause denial of service in Go-Ethereum nodes by sending excessive messages due to missing memory handling in the ethash algorithm.

- **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:** 16 Mar 2022
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-vrcc-g6vj-mh5w

## What is CVE-2021-42219?

CVE-2021-42219 is a high-severity denial of service vulnerability in n/a, published on 16 Mar 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Go-Ethereum v1.10.9 was discovered to contain an issue which allows attackers to cause a denial of service (DoS) via sending an excessive amount of messages to a node. This is caused by missing memory in the component /ethash/algorithm.go.

## Which versions are affected by CVE-2021-42219?

2 open source packages ship an affected version, including github.com/ethereum/go-ethereum. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/ethereum/go-ethereum` | Go | All versions to 1.10.9 | None |
| `github.com/ethereum/go-ethereum` | Go | All versions to 1.10.9 | None |

Products: Ethereum Go Ethereum.

## How do I fix CVE-2021-42219?

No fix has been published for CVE-2021-42219 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42219 being exploited?

There is no known exploitation of CVE-2021-42219 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-26314](https://insights.sbomify.com/CVE-2026-26314/): Go Ethereum affected by DoS via malicious p2p message (high 8.7)
- [CVE-2023-42319](https://insights.sbomify.com/CVE-2023-42319/): go-ethereum vulnerable to denial of service via crafted GraphQL query (high 7.5)
- [CVE-2023-40591](https://insights.sbomify.com/CVE-2023-40591/): Denial of service via malicious p2p message in go-ethereum (high 7.5)
- [CVE-2022-23327](https://insights.sbomify.com/CVE-2022-23327/): Denial of Service in Go-Ethereum (high 7.5)
- [CVE-2022-23328](https://insights.sbomify.com/CVE-2022-23328/): Denial of Service in Go-Ethereum (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42219 and fix it if it is affected.

What it is: CVE-2021-42219 is a high-severity denial of service vulnerability in n/a, published on 16 Mar 2022. 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-2021-42219 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/ethereum/go-ethereum (Go): affected all versions up to 1.10.9; no fix listed
- github.com/ethereum/go-ethereum (Go): affected all versions up to 1.10.9; no fix listed

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-2021-42219/ (Markdown: https://insights.sbomify.com/CVE-2021-42219/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42219
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42219
- OSV: https://osv.dev/vulnerability/CVE-2021-42219

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42219/
Summaries are generated and may contain mistakes; the official description above is the record.