# MAL-2026-5310: Malicious code in regexp-ts (npm)


- **Type:** Malicious package
- **Package:** `regexp-ts` (npm)
- **Published:** 8 Jun 2026
- **Also known as:** GHSA-5p9w-932r-cr5f

## What is MAL-2026-5310?

MAL-2026-5310 is a malicious package in regexp-ts, published on 8 Jun 2026. 

### Official description

regexp-ts masquerades as the pino logger (description, keywords, and `module.exports.pino` export) but is actually a remote-code-execution loader. When a consumer imports the package and invokes its middleware export, index.js unconditionally spawns lib/caller.js as a detached Node process. caller.js performs an HTTP GET to https://jsonkeeper.com/b/U2BTS, takes the `cookie` field of the JSON response, and runs it via `new Function.constructor('require', s)(require)` — executing arbitrary attacker-controlled JavaScript with full Node.js privileges and access to the host's `require`. Additional payload URLs (https://jsonkeeper.com/b/XRGF3 and https://jsonkeeper.com/b/4NAKK) are hidden as base64 strings in lib/const.js under cover names like `DEV_API_KEY`/`DEV_SECRET_KEY` to evade casual review. Because the payload host is a free anonymous JSON paste service, the executed code is mutable at any time without a package update.

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-2026-5310?

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-2026-5310 is a malicious package: regexp-ts (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-2026-5310/ (Markdown: https://insights.sbomify.com/MAL-2026-5310/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5310

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5310/
Summaries are generated and may contain mistakes; the official description above is the record.