# MAL-2026-6316: Malicious code in ts-biginteger-lib (npm)


- **Type:** Malicious package
- **Package:** `ts-biginteger-lib` (npm)
- **Published:** 23 Jun 2026
- **Also known as:** GHSA-6v6m-rhh8-ww9v

## What is MAL-2026-6316?

MAL-2026-6316 is a malicious package in ts-biginteger-lib, published on 23 Jun 2026. 

### Official description

Package is published as 'ts-biginteger-lib' but its metadata, README, and source are a wholesale copy of big.js by MikeMcl (author set to 'Michael Mclaughlin <M8ch88l@gmail.com>', repository pointing at MikeMcl/big.js, README unchanged). Inserted into the otherwise-verbatim big.js source at big.js:605-609 is a try/catch that, at module load time, calls `require("ts-lint-builders")` and invokes `doc.from_str().then(...).catch(...)`. package.json additionally declares `"ts-linter-builders": "latest"` as a runtime dependency. The legitimate big.js declares no runtime dependencies; these injected loads execute arbitrary code from separately-published, attacker-controlled packages every time a consumer `require()`s or `import`s ts-biginteger-lib. The unpinned `latest` specifier lets the publisher rotate the payload at any time without modifying this package. The combination of brand impersonation (to attract installers searching for a TypeScript big-integer library) and require-time execution of an external, version-floating dependency is a supply-chain dropper.

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-2026-6316?

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-2026-6316 is a malicious package: ts-biginteger-lib (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-2026-6316/ (Markdown: https://insights.sbomify.com/MAL-2026-6316/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-6316

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-6316/
Summaries are generated and may contain mistakes; the official description above is the record.