CVE-2026-113721

medium

Description

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, ViaTemplateActivator._generate() removes an existing output only when Path.exists() is true, allowing a dangling symlink to survive and redirect generated activation content, while PyEnvCfg.write() opens pyvenv.cfg without first replacing an existing symbolic or hard link. Another local account that prepares final entries inside the destination can therefore cause environment creation to create or overwrite files outside the requested tree with constrained virtualenv-generated content and the invoking user's permissions. The destination parent must remain controlled by the environment owner during creation; concurrent parent-directory replacement is a separate concern. This issue is fixed in version 21.14.9.

References

https://github.com/pypa/virtualenv/security/advisories/GHSA-558c-9hv2-4prj

https://github.com/pypa/virtualenv/releases/tag/21.14.9

https://github.com/pypa/virtualenv/pull/3431

https://github.com/pypa/virtualenv/commit/d25f28699eefb1fc34a251e5adf2b5de844c36cd

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-105303

Details

Source: Mitre, NVD

Published: 2026-10-20

Updated: 2026-10-22

Risk Information

CVSS v2

Base Score: 3.5

Vector: CVSS2#AV:L/AC:H/Au:S/C:P/I:P/A:P

Severity: Low

CVSS v3

Base Score: 4.5

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

Severity: Medium

EPSS

EPSS: 0.00117