MAL-2026-18102Critical▾ Abyssal⚠ Exploited in the wildMalicious code in semveer (PyPI)
▾ Abyssal zone — Critical with a public exploit or in-the-wild use
impact 52.3 · likelihood 0 · exploitation 18
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The sdist for 'semveer' ships an inert module (semveer/init.py contains only a version stub) and places all runtime behavior inside setup.py's install hook. On pip install, setup.py calls urllib.request.urlretrieve against https://c2-worker.crawlnet-claim.workers.dev/dl/pyupd, writes the opaque payload to a temporary file, and launches it via subprocess.Popen with start_new_session=True as a detached process. The fetch is wrapped in a bare try/except that suppresses errors, there is no hash or signature verification, the version is not pinned, and the destination host is unrelated to any declared publisher or project homepage. The package name is a one-character edit of the widely used 'semver' name, consistent with a typosquat lure whose only purpose is to trigger the install-time dropper.
During installation, package downloads and executes malware.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-10-semvver
Reasons (based on the campaign):
Downloads and executes a remote executable.
malware
typosquatting
semveerRefer to the advisory for the patched release.