# MAL-2026-6342: Malicious code in therdweb (npm)


- **Type:** Malicious package
- **Package:** `therdweb` (npm)
- **Published:** 23 Jun 2026
- **Also known as:** GHSA-g2vx-7x66-f2wv

## What is MAL-2026-6342?

MAL-2026-6342 is a malicious package in therdweb, published on 23 Jun 2026. 

### Official description

The package's name 'therdweb' is a one-character variation of the popular 'thirdweb' SDK, while its contents (README, source code, author field 'Michael Mclaughlin', repository URL pointing at MikeMcl/big.js, version banner '7.0.1') are copied verbatim from the unrelated big.js library — the publisher is not the original author of either project. Both shipped entrypoints, big.js and big.mjs, contain an injected try/catch block that performs `require("parket-slot")` and immediately invokes `doc.from_str()` on it at module load, with the catch block left empty to swallow errors. `parket-slot` is not listed in `package.json` dependencies and is not mentioned in the README (which falsely claims 'No dependencies'); package.json additionally declares an undocumented dependency `log-taker@^0.0.9`. Any consumer that imports or requires this package will execute code from these external, undeclared/hidden modules controlled by the same actor, while the README hides their existence. This is the loader half of a multi-package install-graph dropper paired with name-confusion against thirdweb and identity impersonation of big.js.

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-2026-6342?

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-2026-6342 is a malicious package: therdweb (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-2026-6342/ (Markdown: https://insights.sbomify.com/MAL-2026-6342/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6342

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-6342/
Summaries are generated and may contain mistakes; the official description above is the record.