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BIT-virtualenv-2026-22702 — virtualenv Has TOCTOU Vulnerabilities in Directory Creation

Affected: Bitnami: virtualenv

virtualenv is a tool for creating isolated virtual python environments. Prior to version 20.36.1, TOCTOU (Time-of-Check-Time-of-Use) vulnerabilities in virtualenv allow local attackers to perform symlink-based attacks on directory creation operations. An attacker with local access can exploit a race condition between directory existence checks and creation to redirect virtualenv's app_data and lock file operations to attacker-controlled locations. This issue has been patched in version 20.36.1.

CVE-2026-22702 — virtualenv Has TOCTOU Vulnerabilities in Directory Creation

Affected: pypa virtualenv

GHSA-597g-3phw-6986 — virtualenv Has TOCTOU Vulnerabilities in Directory Creation

Affected: PyPI: virtualenv

## Impact

TOCTOU (Time-of-Check-Time-of-Use) vulnerabilities in `virtualenv` allow local attackers to perform symlink-based attacks on directory creation operations. An attacker with local access can exploit a race condition between directory existence checks and creation to redirect virtualenv's app_data and lock file operations to attacker-controlled locations.

**Affected versions:** All versions up to and including 20.36.1

**Affected users:** Any user running `virtualenv` on multi-user systems where untrusted local users have filesystem access to shared temporary directories or where `VIRTUALENV_OVERRIDE_APP_DATA` points to a user-writable location.

**Attack scenarios:** - Cache poisoning: Attacker corrupts wheels or Python metadata in the cache - Information disclosure: Attacker reads sensitive cached data or metadata - Lock bypass: Attacker controls lock file semantics to cause concurrent access violations - Denial of service: Lock starvation preventing virtualenv operations

## Patches

The vulnerability has been patched by replacing check-then-act patterns with atomic `os.makedirs(..., exist_ok=True)` operations.

**Fixed in:** PR #3013

**Versions with the fix:** 20.36.2 and later

Users should upgrade to version 20.36.2 or later.

## Workarounds

If you cannot upgrade immediately:

1. Ensure `VIRTUALENV_OVERRIDE_APP_DATA` points to a directory owned by the current user with restricted permissions (mode 0700) 2. Avoid running `virtualenv` in shared temporary dire…

PYSEC-2026-2009 — virtualenv Has TOCTOU Vulnerabilities in Directory Creation