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.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-PYTHON-VIRTUALENV-21282510
- published21 Oct 2026
- disclosed20 Oct 2026
- creditAnthropic's OSS Scanner
Introduced: 20 Oct 2026
NewCVE-2026-113724 (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 onerror handler in src/virtualenv/util/path/_sync.py during directory tree removal on Windows. When a read-only file or directory cannot be deleted, the handler widens the entry's permissions using os.chmod before retrying the deletion, creating a race window in which another local user can access the target path with the temporarily elevated mode. An attacker who can traverse the parent directories of the target can exploit this window to read or modify files they would otherwise be denied access to.
Note: This is only exploitable if another account can traverse the target's parent directories, and the widened mode is applied only transiently during the deletion retry on Windows.