# MAL-2026-6278: Malicious code in ts-wross (npm)


- **Type:** Malicious package
- **Package:** `ts-wross` (npm)
- **Published:** 23 Jun 2026
- **Also known as:** GHSA-53h7-mc3v-w73c

## What is MAL-2026-6278?

MAL-2026-6278 is a malicious package in ts-wross, published on 23 Jun 2026. 

### Official description

Package is published under the name `ts-wross` but its package.json claims authorship by Michael Mclaughlin (M8ch88l@gmail.com) and points its repository field at https://github.com/MikeMcl/big.js.git, with description and keywords copied from the legitimate big.js arbitrary-precision arithmetic library. The shipped source is a verbatim copy of big.js v7.0.1 with one modification: a try/catch block injected mid-file in both `big.js` and `big.mjs` that runs `const doc = require("node-slot"); doc.from_str().then(...).catch(...)` at module load. Errors are swallowed by the surrounding try/catch so the call is silent. `node-slot` is declared as a runtime dependency (`"node-slot": "^1.0.8"`) and is therefore pulled in and executed on any `require('ts-wross')` / `import 'ts-wross'`. The legitimate big.js has zero dependencies and no such call — the inserted require is a loader trampoline that hands import-time execution on the installer's machine to whatever code `node-slot` ships. Combined with the impersonated metadata, the package is a lure that drops attacker-controlled code into any consumer that installs it under the assumption it is or relates to 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-2026-6278?

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-2026-6278 is a malicious package: ts-wross (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-2026-6278/ (Markdown: https://insights.sbomify.com/MAL-2026-6278/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6278

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-6278/
Summaries are generated and may contain mistakes; the official description above is the record.