MAL-2026-5876None▾ SunlitMalicious code in temp-development-package-test (PyPI)
▾ Sunlit zone — Low / medium · no exploitation signal
impact 2.8 · likelihood 0 · exploitation 0
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Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
-= Per source details. Do not edit below this line.=-
setup.py defines install_sitecustomize(), which copies src/temp_development_package_test/setup/sitecustomize.py into the active interpreter's site-packages as sitecustomize.py. Python auto-imports sitecustomize at every interpreter start, making this a classic persistence / auto-execute primitive that would run arbitrary code in every Python invocation in that environment. In this released tarball the source payload file is absent, so the install raises FileNotFoundError and no file is dropped — meaning this version causes no installer harm. However, the package name ("temp-development-package-test") plus the staged copy mechanism plus an unused import base64 in setup.py indicates the author is iterating on a supply-chain primitive. A future release that includes the payload file would silently install a global Python interpreter hook on every pip install. Recommend human review of this maintainer/account and rejection of any subsequent version that ships the sitecustomize.py file.
Starting with version 0.4, package installs a sitecustomize.py that executes during Python engine initialization. The embeded code uses mshta to download malicious code, as in other packages from the campaign.
Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.
Campaign: 2026-06-easyaillm
Reasons (based on the campaign):
Downloads and executes a remote executable.
obfuscation
malware
tool:mshta
temp-development-package-testRefer to the advisory for the patched release.