# MAL-2026-4828: Malicious code in hmacsync (PyPI)


- **Type:** Malicious package
- **Package:** `hmacsync` (PyPI)
- **Published:** 26 May 2026

## What is MAL-2026-4828?

MAL-2026-4828 is a malicious package in hmacsync, published on 26 May 2026. 

### Official description

The package is a new version of the previously removed libhmac. The key parts, a malicious payload to inject into hijacked browser extensions, is not included in the package. The code allows hijacking browser extensions to - based on previous package - exfiltrate credentials. This package also contains code to create hidden SSH access to the machine with hardcoded credentials.

---

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

Campaign: 2026-05-libhmac

Reasons (based on the campaign):

 - crypto-related

 - exfiltration-credentials

 - exfiltration-crypto

 - exfiltration-browser-data

## What should I do about MAL-2026-4828?

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-2026-4828 is a malicious package: hmacsync (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-2026-4828/ (Markdown: https://insights.sbomify.com/MAL-2026-4828/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4828

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-4828/
Summaries are generated and may contain mistakes; the official description above is the record.