Downloaded seed wheels (pip/setuptools) are not integrity-checked before use
download_wheel() runs pip download and hands the result straight to the
seeder, with nothing checking the bytes it gets back. The embedded pip and
setuptools wheels carry a BUNDLE_SHA256 that virtualenv checks on every load,
but a wheel fetched over the network for the periodic-update feature or the
--download flag had no equivalent verification.
A compromised index, a stale mirror, or a MITM'd download (when TLS is intercepted, e.g. via a misconfigured or malicious CA) could substitute a different wheel under the same distribution/version/filename, and virtualenv would cache and seed it into every environment created afterward with no warning.
Fixed in 21.7.12 by computing the downloaded wheel's sha256 and comparing it
against the digest PyPI's public JSON API reports for that exact release,
independent of which index actually served the file. The check is skipped, not
treated as failure, when a custom index (PIP_INDEX_URL,
PIP_EXTRA_INDEX_URL, PIP_INDEX) is configured, since a private index can
legitimately serve a different, intentionally rebuilt wheel.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | virtualenv | < 21.7.12 | 21.7.12 |
References
- https://github.com/pypa/virtualenv/security/advisories/GHSA-94p9-xgh2-xp45
- https://nvd.nist.gov/vuln/detail/CVE-2026-102930
- https://github.com/pypa/virtualenv/pull/3251
- https://github.com/pypa/virtualenv/commit/a01ed3e2f239d6ab1fce62c5c7664ccf268fff6d
- https://github.com/pypa/advisory-database/tree/main/vulns/virtualenv/PYSEC-2026-4011.yaml
- https://github.com/pypa/virtualenv
- https://github.com/pypa/virtualenv/releases/tag/21.7.12
- https://pypi.org/project/virtualenv
- CVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-494- Platform
- Python (PyPI)
- Package
virtualenv- Disclosed
- 18.09.2026
- Updated
- 11.10.2026 15:18
Sources and licenses
OSV / GitHub Advisory Database - GHSA-94p9-xgh2-xp45 - CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2026-4011 - PyPA Advisory Database; CC BY 4.0
Vulnerability history: virtualenv
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 7
- First → latest
- 12.2011 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 4
- Medium 3
Disclosures per year
- 2017: 0
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 5
earlier: 1
-
Downloaded seed wheels (pip/setuptools) are not integrity-checked before use this entry
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