CVE-2026-22702

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

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

Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing. Typical impact: TOCTOU exploits, data corruption, or privilege escalation.

CVE-2026-22702 has a CVSS score of 4.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (20.36.1); upgrading removes the vulnerable code path.

Kodem intelligence

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.

1. What is CVE-2026-22702? CVE-2026-22702 is a medium-severity race condition vulnerability in virtualenv (pip), affecting versions < 20.36.1. It is fixed in 20.36.1. Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing.
2. How severe is CVE-2026-22702? CVE-2026-22702 has a CVSS score of 4.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of virtualenv are affected by CVE-2026-22702? virtualenv (pip) versions < 20.36.1 is affected.
4. Is there a fix for CVE-2026-22702? Yes. CVE-2026-22702 is fixed in 20.36.1. Upgrade to this version or later.
5. Is CVE-2026-22702 exploitable, and should I be worried? Whether CVE-2026-22702 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-22702 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-22702? Upgrade virtualenv to 20.36.1 or later.