virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, download_wheel() writes package-index downloads directly into the reusable wheel/house cache before selecting a verification target from pip's textual Saved output. With default-index digest comparison enabled, a controlled package index can inject a misleading Saved line through a discarded link's data-requires-python attribute; this forged-line variant also requires knowledge of an absolute path to the genuine bundled wheel. The wrong path can then be hashed, while a digest mismatch leaves the rejected archive in the cache for later selection without verification. A separate rejected-cache-file variant requires control over downloaded data or archive selection but not the forged-line prerequisites. Explicit custom-index exceptions are outside the promised PyPI comparison, and the issue does not independently bypass TLS or establish control of default PyPI. This issue is fixed in version 21.14.9.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 5
- StatusAwaiting Analysis → PublishedNVD modified 2026-10-27 10:59
- StatusPublished → Awaiting AnalysisNVD modified 2026-10-27 11:17
- StatusAwaiting Analysis → PublishedNVD modified 2026-10-20 19:19
- DescriptionNVD modified 2026-10-20 20:17
virtualenv is a tool for creating isolated virtual python environments. From 21.14.8 until 21.14.9, download_wheel() writes package-index downloads directly into the reusable wheel/house cache before selecting a verification target from pip's textual Saved output. With default-index digest comparison enabled, a controlled package index can inject a misleading Saved line through a discarded link's data-requires-python attribute; this forged-line variant also requires knowledge of an absolute path to the genuine bundled wheel. The wrong path can then be hashed, while a digest mismatch leaves the rejected archive in the cache for later selection without verification. A separate rejected-cache-file variant requires control over downloaded data or archive selection but not the forged-line prerequisites. Explicit custom-index exceptions are outside the promised PyPI comparison, and the issue does not independently bypass TLS or establish control of default PyPI. This issue is fixed in version 21.14.9.virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, download_wheel() writes package-index downloads directly into the reusable wheel/house cache before selecting a verification target from pip's textual Saved output. With default-index digest comparison enabled, a controlled package index can inject a misleading Saved line through a discarded link's data-requires-python attribute; this forged-line variant also requires knowledge of an absolute path to the genuine bundled wheel. The wrong path can then be hashed, while a digest mismatch leaves the rejected archive in the cache for later selection without verification. A separate rejected-cache-file variant requires control over downloaded data or archive selection but not the forged-line prerequisites. Explicit custom-index exceptions are outside the promised PyPI comparison, and the issue does not independently bypass TLS or establish control of default PyPI. This issue is fixed in version 21.14.9. - First seenCVSS 2.3NVD modified 2026-10-20 19:59
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 5
- https://github.com/pypa/virtualenv/commit/7babec66e043e1cc8bc66869a063653898719d96
- https://github.com/pypa/virtualenv/pull/3430
- https://github.com/pypa/virtualenv/releases/tag/21.14.9
- https://github.com/pypa/virtualenv/security/advisories/GHSA-494p-63j8-28p3
- https://github.com/pypa/virtualenv/security/advisories/GHSA-494p-63j8-28p3