{"id":"MAL-2026-18093","title":"Malicious code in workcalender (PyPI)","summary":"Malicious code in workcalender (PyPI)","severity":"critical","exploited":true,"vendor":"workcalender","product":"workcalender","ecosystem":"pip","affected":["workcalender"],"published":"2026-10-20","updated":"2026-10-29","sourceUpdated":"2026-10-29T14:45:12.378122679Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/MAL-2026-18093","references":[{"url":"https://bad-packages.kam193.eu/pypi/package/workcalender"},{"url":"https://pypi.org/project/workcalender/17.1.0.dev0/"}],"tags":["osv","pip","malware"],"ingestedAt":"2026-10-21T11:54:42.739Z","slug":"MAL-2026-18093","body":"## Overview\n\n\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (e6a50d22163d9cc8d0eda40abaaa32d88d5c8657ce914ba8b8c792a16cb5ca58)\nAnalysis of the package's shipped files produced no indicators of installer-side harm: no install-time or import-time network I/O, no credential or environment scraping, no fetch-and-execute pattern, no lifecycle shell execution, no silent relay of caller data to a hardcoded destination, and no persistence or backdoor mechanism. The package appears to be a small or developmental release with no observable supply-chain attack surface.\n\n## Source: kam193 (9a336c0fa7a5b3ee5f036d678c8c0f0d549135a08d05549ee92cb11b1a7f78fa)\nThis 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.\n\n\n---\n\nCategory: MALICIOUS - The campaign has clearly malicious intent, like infostealers.\n\n\nCampaign: 2026-10-test-workalendar-internal\n\n\nReasons (based on the campaign):\n\n\n - backdoor\n\n\n - The package overrides the install command in setup.py to execute malicious code during installation.\n\n\n## Affected packages\n\n- `workcalender`\n\n## Remediation\n\nRefer to the advisory for the patched release.","depth":"abyssal","depthScore":70,"depthScoreParts":{"impact":52.3,"likelihood":0,"exploitation":18,"ransomware":0},"changes":[]}