CVE-2026-22702 is a Time-of-Check-Time-of-Use (TOCTOU) race condition vulnerability in the virtualenv tool, versions prior to 20.36.1. Virtualenv is widely used to create isolated Python environments, commonly employed in development and deployment pipelines. The vulnerability arises due to improper link resolution before file access (CWE-59) and a race condition (CWE-362) during directory creation operations. Specifically, virtualenv performs a check to see if a directory exists and then attempts to create it if absent. An attacker with local access can exploit the time gap between these operations by replacing the directory path with a symbolic link pointing to an attacker-controlled location. This redirection affects virtualenv's app_data and lock file operations, potentially allowing the attacker to manipulate or corrupt files that virtualenv relies on. Although exploitation requires local access and elevated privileges, the impact includes limited confidentiality, integrity, and availability degradation, such as unauthorized file modification or denial of service in the virtual environment setup. The vulnerability has been addressed in virtualenv version 20.36.1 by fixing the TOCTOU race condition and ensuring proper link resolution before file operations. No known exploits are currently reported in the wild.

For European organizations, the primary impact is on development, testing, and continuous integration environments where virtualenv is used extensively. Successful exploitation could allow an attacker with local access to interfere with Python environment setups, potentially leading to corrupted environments, unauthorized code execution in some scenarios, or denial of service in automated pipelines. This could disrupt software development lifecycles, delay deployments, and introduce risks of further compromise if attackers manipulate environment files. Confidentiality impact is limited since the attacker must already have local access, but integrity and availability impacts are more significant. Organizations relying heavily on Python for critical applications or infrastructure automation may face operational disruptions. The risk is heightened in shared or multi-user systems where local privilege boundaries are less strictly enforced.

The most effective mitigation is to upgrade all virtualenv installations to version 20.36.1 or later, where the vulnerability is patched. Organizations should audit their environments to identify and remediate outdated virtualenv versions, especially on developer workstations, build servers, and CI/CD infrastructure. Restrict local access to trusted users only, enforcing strict access controls and user privilege separation to reduce the likelihood of local attackers exploiting the race condition. Employ filesystem monitoring to detect suspicious symbolic link creations or modifications in directories used by virtualenv. Additionally, consider running virtual environment creation processes with minimal privileges and within isolated containers or sandboxes to limit the impact of potential exploitation. Regularly review and update development tools and dependencies to incorporate security patches promptly.