# MAL-2026-18092: Malicious code in test-workalendar-internal (PyPI)


- **Type:** Malicious package
- **Package:** `test-workalendar-internal` (PyPI)
- **Published:** 20 Oct 2026

## What is MAL-2026-18092?

MAL-2026-18092 is a malicious package in test-workalendar-internal, published on 20 Oct 2026. 

### Official description

test-workalendar-internal 0.0.3 ships a custom Hatchling build hook that runs during `pip install` (sdist/wheel build). The hook downloads two standalone binaries — ttyd from github.com/tsl0922/ttyd and cloudflared from github.com/cloudflare/cloudflared — to /tmp/ttyd and /tmp/cloudflared, chmods them executable, and spawns ttyd bound to 127.0.0.1:7681 serving an interactive `bash` shell protected only by a generated basic-auth user/password. It then launches `cloudflared tunnel --url http://127.0.0.1:7681`, parses the resulting `*.trycloudflare.com` URL from cloudflared's stdout, and POSTs a JSON payload containing the tunnel URL, username, and password to the hardcoded collector https://webhook.site/f03cbdbe-704b-4932-a0a7-847d749c19b6. The combined effect is a fully automatic install-time remote shell on the installer's host: a remote party receives the public tunnel URL and basic-auth credentials and can interact with bash on the installer's machine. The package's declared purpose (a weekday/calendar helper) is unrelated to web terminals or tunnels.

During build, the package creates a web-sharable terminal session and exposes it via a Cloudflare tunnel to the attacker.

---

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

Campaign: 2026-10-test-workalendar-internal

Reasons (based on the campaign):

 - backdoor

 - The package overrides the install command in setup.py to execute malicious code during installation.

## What should I do about MAL-2026-18092?

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-2026-18092 is a malicious package: test-workalendar-internal (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-2026-18092/ (Markdown: https://insights.sbomify.com/MAL-2026-18092/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-18092

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-18092/
Summaries are generated and may contain mistakes; the official description above is the record.