CVE-2026-102930: virtualenv: Downloaded seed wheels (pip/setuptools) are not integrity-checked before use

Severity: high (CVSS 7.7 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-29 · updated 2026-09-30
Weakness: CWE-494

Description

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.7.12, download_wheel() accepts pip and setuptools seed wheels fetched for periodic updates or the --download option without checking their bytes against an authoritative digest equivalent to the embedded wheels' BUNDLE_SHA256 verification. A compromised index, stale mirror, or intercepted TLS connection can substitute a different wheel under the requested distribution, version, and filename, after which virtualenv caches and seeds the attacker-controlled wheel into subsequently created environments. The verification applies to the default PyPI path and is intentionally skipped when PIP_INDEX_URL, PIP_EXTRA_INDEX_URL, or PIP_INDEX configures a custom index that may legitimately publish rebuilt wheels. This issue is fixed in version 21.7.12.

Affected products

Pypi Virtualenv: before 21.7.12; 0.8, 0.8.1, 0.8.2, 0.8.3, 0.8.4, 0.9 (+275) — fixed in 21.7.12
pypa virtualenv: before 21.7.12

How to fix

Upgrade to a fixed version: Pypi Virtualenv 21.7.12. Check the vendor advisory for mitigations.

References

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