CVE-2026-22702

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 directories where other users have write access
3. Use separate user accounts for different projects to isolate app_data directories

References

• GitHub PR: https://github.com/pypa/virtualenv/pull/3013
• Vulnerability reported by: @tsigouris007
• CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization (TOCTOU)
• CWE-59: Improper Link Resolution Before File Access

Virtualenv is a tool to create isolated Python environments. Since Python 3.3, a subset of it has been integrated into the standard library under the venv module. Note though, that the venv module does not offer all features of this library (e.g. cannot create bootstrap scripts, cannot create virtual environments for other python versions than the host python, not relocatable, etc.). Tools in general as such still may prefer using virtualenv for its ease of upgrading (via pip), unified handling of different Python versions and some more advanced features.

Security Fix(es):

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 is a tool to create isolated Python environments. Since Python 3.3, a subset of it has been integrated into the standard library under the venv module. Note though, that the venv module does not offer all features of this library (e.g. cannot create bootstrap scripts, cannot create virtual environments for other python versions than the host python, not relocatable, etc.). Tools in general as such still may prefer using virtualenv for its ease of upgrading (via pip), unified handling of different Python versions and some more advanced features.

Security Fix(es):

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 is a tool to create isolated Python environments. Since Python 3.3, a subset of it has been integrated into the standard library under the venv module. Note though, that the venv module does not offer all features of this library (e.g. cannot create bootstrap scripts, cannot create virtual environments for other python versions than the host python, not relocatable, etc.). Tools in general as such still may prefer using virtualenv for its ease of upgrading (via pip), unified handling of different Python versions and some more advanced features.

Security Fix(es):

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 is a tool to create isolated Python environments. Since Python 3.3, a subset of it has been integrated into the standard library under the venv module. Note though, that the venv module does not offer all features of this library (e.g. cannot create bootstrap scripts, cannot create virtual environments for other python versions than the host python, not relocatable, etc.). Tools in general as such still may prefer using virtualenv for its ease of upgrading (via pip), unified handling of different Python versions and some more advanced features.

Security Fix(es):

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)

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 directories where other users have write access
3. Use separate user accounts for different projects to isolate app_data directories

References

• GitHub PR: https://github.com/pypa/virtualenv/pull/3013
• Vulnerability reported by: @tsigouris007
• CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization (TOCTOU)
• CWE-59: Improper Link Resolution Before File Access

Root has patched CVE-2026-22702 in the virtualenv package for Root:PyPI. Multiple fixed versions available.

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.

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.

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.

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.

These are all security issues fixed in the python311-virtualenv-20.36.1-1.1 package on the GA media of openSUSE Tumbleweed.

This update for python-virtualenv fixes the following issues:

• CVE-2026-22702: Fixed local attacker can redirect file operations via TOCTOU race condition (bsc#1256458).

This update for python-virtualenv fixes the following issues:

• CVE-2026-22702: Fixed local attacker can redirect file operations via TOCTOU race condition (bsc#1256458).

This update for python-virtualenv fixes the following issues:

• CVE-2026-22702: Fixed local attacker can redirect file operations via TOCTOU race condition (bsc#1256458).