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Vulnerability · Published Oct 20, 2026 · Assigned by GitHub_M

CVE-2026-113716virtualenv: Builtin creation follows linked environment directories

Medium 4.5

In plain English

A medium-severity security flaw in virtualenv from pypa. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.5Medium
Exploit odds (30 days)0.1%top 96.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, the builtin creator calls ensure_dir() for executable, library, and package directories, and ensure_dir() accepts an existing symlink to a directory because exists() follows it. Interpreter creation, seed installation, and activation generation then write through the linked parent outside the requested destination when another local account prepared the tree and the invoking user can access the target. The --clear option removes the planted tree first, while ordinary creation reaches it; arbitrary attacker-selected output bytes are not established. This issue is fixed in version 21.14.9.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12python-virtualenvno fix listedDEBIAN-CVE-2026-113716
Debian:13python-virtualenvno fix listedDEBIAN-CVE-2026-113716
Debian:14python-virtualenvno fix listedDEBIAN-CVE-2026-113716
PyPIvirtualenv21.14.9GHSA-cw65-gx24-rc82
Ubuntu:26.04:LTSpython-virtualenvno fix listedUBUNTU-CVE-2026-113716
Ubuntu:26.10python-virtualenvno fix listedUBUNTU-CVE-2026-113716

Affected products (as reported)

VendorProductVersions
pypa virtualenv < 21.14.9

Weakness: CWE-59 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

References