CVE-2026-22702Medium· 4.5▾ Sunlitvirtualenv Has TOCTOU Vulnerabilities in Directory Creation
▾ Sunlit zone — Low / medium · no exploitation signal
impact 24.8 · likelihood 0 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
0.08%
0.08% → 0.10%
Last analysed / modified upstream
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:
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.
If you cannot upgrade immediately:
VIRTUALENV_OVERRIDE_APP_DATA points to a directory owned by the current user with restricted permissions (mode 0700)virtualenv in shared temporary directories where other users have write accessvirtualenv < 20.36.1Upgrade to a patched release:
virtualenv 20.36.1Connected by shared product, vendor, weakness, or advisory.