# MAL-2026-11991: Malicious code in verdaccio-tarball-local-storage (npm)


- **Type:** Malicious package
- **Package:** `verdaccio-tarball-local-storage` (npm)
- **Published:** 4 Aug 2026
- **Also known as:** GHSA-9gjj-ggwr-8h6x

## What is MAL-2026-11991?

MAL-2026-11991 is a malicious package in verdaccio-tarball-local-storage, published on 4 Aug 2026. 

### Official description

npm/verdaccio-tarball-local-storage is affected by the large-scale, self-propagating npm supply-chain worm of 2026-08-04 (the "Shai-Hulud: Here We Go Again" wave) — the same campaign that began with the compromise of the keyv and cacheable maintainer account. The listed version(s) were trojanized and republished by the worm after it reached an npm publish token belonging to a maintainer in this namespace; the payload enumerates every package a stolen token controls and republishes each with the same hook, so many packages under this scope were poisoned in the same short window. Every poisoned release adds a preinstall hook (`"preinstall": "node setup.mjs"`) that runs on a bare `npm install`, before any project code. setup.mjs downloads a standalone Bun runtime and runs a byte-identical, heavily obfuscated ~728 KB second-stage credential stealer (shipped as Math_Symbol.js / math_init.js). It harvests GitHub, npm, AWS, GCP, Azure, HashiCorp Vault and Kubernetes credentials plus generic secrets and private keys (TruffleHog-style sweep), reads CI/CD secrets and identifies build runners, then republishes further packages the stolen token can reach. Rather than a fixed command-and-control host, it exfiltrates stolen findings to attacker-created GitHub repositories (descriptions reading "Shai-Hulud: Here We Go Again") and over DNS. Treat any environment that installed an affected version (with install scripts enabled) as compromised: rotate and revoke all reachable credentials (npm and GitHub tokens, cloud keys, Vault/Kubernetes secrets, and CI org/repo secrets). Part of the August 2026 npm worm that poisoned 400+ packages across many organizations.

The npm package's `preinstall` hook runs `node setup.mjs`, which prefers a system `bun` binary and otherwise downloads a Bun runtime archive from a GitHub releases URL constructed at runtime, unpacks it to a temp directory, chmods the extracted binary 0o755, and invokes it against the sibling file `math_init.js` via `execFileSync`. `math_init.js` is a 727 KB single-line, heavily obfuscated JavaScript blob (character-array rotator plus a large custom Base64-style alphabet constant, matching the obfuscator.io shape) that is never referenced by the plugin's advertised entry (`dist/index.js`) and is only reachable through the freshly downloaded Bun runtime. The package name `verdaccio-tarball-local-storage` closely resembles the legitimate `@verdaccio/local-storage`, and the benign-looking `dist/index.js` presents a plausible Verdaccio-plugin cover while the actual install-time behavior is an alternate-runtime dropper that executes an opaque bundled payload on `npm install`. This is the alternate-runtime-dropper fingerprint: a second language runtime is fetched at install specifically to execute a bundled obfuscated blob outside the Node-based execution path that most scanners inspect.

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-2026-11991?

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-2026-11991 is a malicious package: verdaccio-tarball-local-storage (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-2026-11991/ (Markdown: https://insights.sbomify.com/MAL-2026-11991/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-11991

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-11991/
Summaries are generated and may contain mistakes; the official description above is the record.