# MAL-2026-4262: Malicious code in solidity-build-guard (PyPI)


- **Type:** Malicious package
- **Package:** `solidity-build-guard` (PyPI)
- **Published:** 22 May 2026

## What is MAL-2026-4262?

MAL-2026-4262 is a malicious package in solidity-build-guard, published on 22 May 2026. 

### Official description

On `import solidity_build_guard`, the top-level `__init__.py` (lines 11-24) shells out to curl to download a JavaScript file from a personal GitHub Pages URL (https://ddjidd564.github.io/defi-security-best-practices/payloads/compiler-guard.js) and pipes the response directly to `node -e` for execution. The URL is unpinned, mutable, served from a non-publisher personal account, and unrelated to the package's advertised Solidity-version-checking purpose; no hash or signature check is performed on the fetched bytes. The dropper is gated by a once-per-process flag (`sys._compiler_guard_active`) and wrapped in a bare `try/except: pass` so failures are silenced, with a cover-story comment ('Auto-verify on import (runs once)') framing the call as a legitimate guard. Any environment that imports this package — developer machines, CI runners, build pipelines — executes attacker-controlled JavaScript with the installer's privileges, and the payload can be swapped at any time without republishing the package. The module also requires Node.js to be present on the host and pivots execution into an alternate runtime, evading Python-only sandboxing.

During import, the package downloads a remote JS script that then exfiltrates environmental variables, dotenv files, cryptowallets data and other sensitive informations. It's part of a broader campaign across PyPI, NPM and Github.

---

Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.

Campaign: 2026-05-eth-security-auditor

Reasons (based on the campaign):

 - files-exfiltration

 - exfiltration-env-variables

 - crypto-related

 - Downloads and executes a remote malicious script.

 - exfiltration-crypto

 - exfiltration-credentials

## What should I do about MAL-2026-4262?

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-2026-4262 is a malicious package: solidity-build-guard (PyPI). 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-2026-4262/ (Markdown: https://insights.sbomify.com/MAL-2026-4262/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4262

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-4262/
Summaries are generated and may contain mistakes; the official description above is the record.