Symlink Attack Affecting virtualenv package, versions [21.14.8,21.14.10)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-VIRTUALENV-21282425
- published21 Oct 2026
- disclosed20 Oct 2026
- creditUnknown
Introduced: 20 Oct 2026
NewCVE-2026-113713 (opens in a new tab)How to fix?
Upgrade virtualenv to version 21.14.10 or higher.
Overview
Affected versions of this package are vulnerable to Symlink Attack via the FromAppData seed mechanism in src/virtualenv/seed/embed/via_app_data/via_app_data.py, when symlink_app_data is enabled against a transient (temporary) app-data store. In this configuration, virtualenv creates symlinks from the newly created virtual environment's seed packages to temporary files that are deleted after setup completes, leaving the environment with dangling symlinks. An attacker who can write to the temporary directory before or after deletion can substitute malicious package files that the virtual environment then resolves through those symlinks, leading to arbitrary code execution within the environment.
Note: This is only exploitable when symlink_app_data is enabled and virtualenv is configured to use a transient app-data store, either via environment variables or configuration files.