CVE-2026-113717

Received Received - Intake

Pip Dependency Verification Bypass in virtualenv

Publication date: 2026-10-20

Last updated on: 2026-10-20

Assigner: GitHub, Inc.

Description

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, PipInvoke.get_pip_install_cmd() handles --seeder pip --download by calling get_wheel(download=False) and then allowing pip to consult the configured index, bypassing virtualenv's download_wheel() and verify_wheel_digest() path. When virtualenv's default-index PyPI digest comparison remains enabled, an index candidate matching the bundled package and version can therefore be selected without comparison to PyPI SHA-256 metadata. Explicit custom-index settings already opt out of that comparison and remain outside this verification-bypass claim; the demonstrated configuration used a non-PyPI index while leaving the index environment variables unset so the comparison policy remained active. This condition does not independently defeat TLS or establish control of the index response. This issue is fixed in version 21.14.9.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-20

Last Modified

2026-10-20

Generated

2026-10-21

AI Q&A

2026-10-21

EPSS Evaluated

N/A

NVD

CVE-2026-113717

EUVD

EUVD-2026-105298

Affected Vendors & Products

Vendor	Product	Version / Range
pypa	virtualenv	< 21.14.9

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-494	The product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.

Attack-Flow Graph

Executive Summary

CVE-2026-113717 is a vulnerability in the virtualenv tool where the pip seeder fails to verify the integrity of downloaded Python wheels when using the --download option. This happens because the seeder bypasses virtualenv's wheel digest verification by allowing pip to access the index directly. An attacker could exploit this by providing a modified wheel with the same filename and version through a custom index, leading to installation of tampered code without detection.

Detection Guidance

Check virtualenv version with pip show virtualenv. If version is below 21.14.9, the system is vulnerable. Review pip seeder usage in virtualenv configurations for --seeder pip --download flags.

Impact Analysis

If you use virtualenv with the --seeder pip and --download options together, an attacker could trick your system into installing a malicious or incorrect Python wheel. This could lead to execution of unintended code in your virtual environment. The vulnerability requires a custom index setup to be exploitable, as default PyPI setups are not affected.

Mitigation Strategies

Upgrade virtualenv to version 21.14.9 or later. Avoid using --seeder pip --download together. Review custom index configurations to ensure digest verification remains active.

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