# MAL-2026-6201: Malicious code in eth-util (npm)


- **Type:** Malicious package
- **Package:** `eth-util` (npm)
- **Published:** 19 Jun 2026
- **Also known as:** GHSA-fq6v-3gxv-7rjv

## What is MAL-2026-6201?

MAL-2026-6201 is a malicious package in eth-util, published on 19 Jun 2026. 

### Official description

Package `eth-util` impersonates the legitimate `@ethereumjs/util` package: README, repository URL (github.com/ethereumjs/ethereumjs-monorepo), badges, contributor list, and module API are copied from the ethereumjs project, but the package is published under the unrelated short name `eth-util`. The compiled `dist/index.js` at line 55 contains a side-effect-only `require("assert-kit")` that is absent from `src/index.ts` and from the parallel `dist.browser/index.js` bundle — tsc would not emit an unreferenced require of a package not present in the source, so this line was injected post-compile. Anyone reading the GitHub source would not see the loader; only the published npm tarball carries it. The `assert-kit` dependency is declared at `^4.3.2` in package.json, mimic-named after the Node built-in `assert` referenced in the README, and the caret range lets the publisher ship arbitrary code into installers via any future minor/patch release. On `require("eth-util")`, the consumer's process executes whatever top-level code `assert-kit` ships.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-6201?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-6201 is a malicious package: eth-util (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-6201/ (Markdown: https://insights.sbomify.com/MAL-2026-6201/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6201

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-6201/
Summaries are generated and may contain mistakes; the official description above is the record.