# MAL-2026-11821: Malicious code in @servicetitan/anvil-token (npm)


- **Type:** Malicious package
- **Package:** `@servicetitan/anvil-token` (npm)
- **Published:** 4 Aug 2026
- **Also known as:** GHSA-g9jv-9f6h-x82w

## What is MAL-2026-11821?

MAL-2026-11821 is a malicious package in @servicetitan/anvil-token, published on 4 Aug 2026. 

### Official description

npm/@servicetitan/anvil-token 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.

package.json declares `"preinstall": "node setup.mjs"`. setup.mjs downloads a Bun runtime from the oven-sh/bun GitHub releases (`https://github.com/oven-sh/bun/releases/download/bun-v<V>/<arch>.zip`), extracts it to a temp directory, chmods it executable, and invokes it against the sibling file math_init.js. math_init.js is a 727KB Bun-compiled JavaScript file (`// @bun @bun-cjs` header) whose contents are heavily obfuscated using obfuscator.io-style string-array rotation (`WV8StW` rotator over a large numeric/char-code table) — not human-readable and undocumented. This executes automatically on `npm install`. The package's documented purpose is shipping design-token JSON theme files, which requires no runtime code execution; the bundled CHANGELOG.md stops at v0.4.0 (March 2024) and does not describe the preinstall hook, setup.mjs, or math_init.js that appear in this 0.4.4 tarball, indicating the lifecycle-executed payload was added outside the package's documented release history. The Bun runtime is used to run attacker-supplied obfuscated code that would otherwise be visible to Node-based tooling; delivery of a runtime plus an opaque payload as an install-time side effect of a design-tokens package is an alternate-runtime dropper pattern.

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-2026-11821?

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-2026-11821 is a malicious package: @servicetitan/anvil-token (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-2026-11821/ (Markdown: https://insights.sbomify.com/MAL-2026-11821/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-11821

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-11821/
Summaries are generated and may contain mistakes; the official description above is the record.