---
id: "MAL-2026-18093"
kind: "package"
aliases: ["MAL-2026-18093"]
title: "Malicious code in workcalender (PyPI)"
severity: "critical"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "workcalender", "fixed": [], "affected": "= 17.1.0.dev0", "ecosystem": "pypi"}]
ecosystems: ["pypi"]
tags: ["malicious", "package"]
not_affected_if: []
published_at: "2026-10-20T13:05:17+00:00"
first_seen_at: "2026-10-26T20:52:00+00:00"
updated_at: "2026-10-26T21:05:48+00:00"
sources: [{"source": "osv-malicious", "url": "https://osv.dev/vulnerability/MAL-2026-18093", "first_seen_at": "2026-10-26T20:52:00+00:00"}]
---

# Malicious code in workcalender (PyPI)

## Affected

- pypi:workcalender affected = 17.1.0.dev0 fixed ?

## Timeline

- 2026-10-26T20:52:00+00:00 osv-malicious https://osv.dev/vulnerability/MAL-2026-18093

## From the sources

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_-= Per source details. Do not edit below this line.=-_

## 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.


---

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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