workcalender

GHSA-rwx2-hxr7-qgg5

Malicious code in workcalender (PyPI)

Details

**Severity:** Critical

**Affected versions:** `= 17.1.0.dev0`

## Source: kam193 (9a336c0fa7a5b3ee5f036d678c8c0f0d549135a08d05549ee92cb11b1a7f78fa)
This package contains a stub build-time helper, which in another package of the same uploader was already turned into a backdoor installation. While this package does not yet contain malicious code, it is clear it was uploaded with such intention and likely exploits dependency confusion.


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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.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/bedf3b347240ede7d500de882787ee4ee4024de9/osv/malicious/pypi/workcalender/MAL-2026-18093.json))

**References:**
- https://bad-packages.kam193.eu/pypi/package/workcalender
- https://github.com/ossf/malicious-packages/blob/bedf3b347240ede7d500de882787ee4ee4024de9/osv/malicious/pypi/workcalender/MAL-2026-18093.json
- https://github.com/advisories/GHSA-rwx2-hxr7-qgg5

Compromised versions (1)

= 17.1.0.dev0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.