Symlink Attack Affecting virtualenv package, versions [21.14.8,21.14.9)
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-21282058
- published21 Oct 2026
- disclosed20 Oct 2026
- creditAnthropic's OSS Scanner
Introduced: 20 Oct 2026
NewCVE-2026-113716 (opens in a new tab)How to fix?
Upgrade virtualenv to version 21.14.9 or higher.
Overview
Affected versions of this package are vulnerable to Symlink Attack via the create method in venv.py and via_global_self_do.py, where output directories are created without first verifying they reside within the intended virtual environment destination. An attacker who can plant a symlink or hard link at an expected output path (such as bin_dir, purelib, or platlib) can cause virtualenv to write files outside the virtual environment boundary, leading to arbitrary file writes in attacker-controlled locations.
Note: This is only exploitable when an attacker can pre-position a symlink or hard link at an expected output directory path before virtualenv creates the environment, and does not require write access to the target itself.