{"id":"PYSEC-2026-2009","summary":"virtualenv Has TOCTOU Vulnerabilities in Directory Creation","details":"## Impact\n\nTOCTOU (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.\n\n**Affected versions:** All versions up to and including 20.36.1\n\n**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.\n\n**Attack scenarios:**\n- Cache poisoning: Attacker corrupts wheels or Python metadata in the cache\n- Information disclosure: Attacker reads sensitive cached data or metadata\n- Lock bypass: Attacker controls lock file semantics to cause concurrent access violations\n- Denial of service: Lock starvation preventing virtualenv operations\n\n## Patches\n\nThe vulnerability has been patched by replacing check-then-act patterns with atomic `os.makedirs(..., exist_ok=True)` operations.\n\n**Fixed in:** PR #3013\n\n**Versions with the fix:** 20.36.2 and later\n\nUsers should upgrade to version 20.36.2 or later.\n\n## Workarounds\n\nIf you cannot upgrade immediately:\n\n1. Ensure `VIRTUALENV_OVERRIDE_APP_DATA` points to a directory owned by the current user with restricted permissions (mode 0700)\n2. Avoid running `virtualenv` in shared temporary directories where other users have write access\n3. Use separate user accounts for different projects to isolate app_data directories\n\n## References\n\n- GitHub PR: https://github.com/pypa/virtualenv/pull/3013\n- Vulnerability reported by: @tsigouris007\n- CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization (TOCTOU)\n- CWE-59: Improper Link Resolution Before File Access","aliases":["BIT-virtualenv-2026-22702","CVE-2026-22702","GHSA-597g-3phw-6986"],"modified":"2026-07-07T17:57:28.238961214Z","published":"2026-07-07T16:03:18.266289Z","references":[{"type":"WEB","url":"https://github.com/pypa/virtualenv/security/advisories/GHSA-597g-3phw-6986"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-22702"},{"type":"WEB","url":"https://github.com/pypa/virtualenv/pull/3013"},{"type":"FIX","url":"https://github.com/pypa/virtualenv/commit/dec4cec5d16edaf83a00a658f32d1e032661cebc"},{"type":"PACKAGE","url":"https://github.com/pypa/virtualenv"},{"type":"PACKAGE","url":"https://pypi.org/project/virtualenv"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-597g-3phw-6986"}],"affected":[{"package":{"name":"virtualenv","ecosystem":"PyPI","purl":"pkg:pypi/virtualenv"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"20.36.1"}]}],"versions":["0.8","0.8.1","0.8.2","0.8.3","0.8.4","0.9","0.9.1","0.9.2","1.0","1.1","1.10","1.10.1","1.11","1.11.1","1.11.2","1.11.3","1.11.4","1.11.5","1.11.6","1.2","1.3","1.3.1","1.3.2","1.3.3","1.3.4","1.4","1.4.1","1.4.2","1.4.3","1.4.4","1.4.5","1.4.6","1.4.7","1.4.8","1.4.9","1.4rc1","1.5","1.5.1","1.5.2","1.6","1.6.1","1.6.2","1.6.3","1.6.4","1.7","1.7.1","1.7.1.1","1.7.1.2","1.7.2","1.8","1.8.1","1.8.2","1.8.3","1.8.4","1.9","1.9.1","12.0","12.0.1","12.0.2","12.0.4","12.0.5","12.0.6","12.0.7","12.1.0","12.1.1","13.0.0","13.0.1","13.0.2","13.0.3","13.1.0","13.1.1","13.1.2","14.0.0","14.0.1","14.0.2","14.0.3","14.0.4","14.0.5","14.0.6","15.0.0","15.0.1","15.0.2","15.0.3","15.1.0","15.2.0","16.0.0","16.1.0","16.2.0","16.3.0","16.3.1.dev0","16.4.0","16.4.1","16.4.3","16.4.4.dev0","16.5.0","16.6.0","16.6.1","16.6.2","16.7.0","16.7.1","16.7.10","16.7.11","16.7.12","16.7.2","16.7.3","16.7.4","16.7.5","16.7.6","16.7.7","16.7.8","16.7.9","20.0.0","20.0.0b1","20.0.0b2","20.0.1","20.0.10","20.0.11","20.0.12","20.0.13","20.0.14","20.0.15","20.0.16","20.0.17","20.0.18","20.0.19","20.0.2","20.0.20","20.0.21","20.0.22","20.0.23","20.0.24","20.0.25","20.0.26","20.0.27","20.0.28","20.0.29","20.0.3","20.0.30","20.0.31","20.0.32","20.0.33","20.0.34","20.0.35","20.0.4","20.0.5","20.0.6","20.0.7","20.0.8","20.0.9","20.1.0","20.10.0","20.11.0","20.11.1","20.11.2","20.12.0","20.12.1","20.13.0","20.13.1","20.13.2","20.13.3","20.13.4","20.14.0","20.14.1","20.15.0","20.15.1","20.16.0","20.16.1","20.16.2","20.16.3","20.16.4","20.16.5","20.16.6","20.16.7","20.17.0","20.17.1","20.18.0","20.19.0","20.2.0","20.2.1","20.2.2","20.20.0","20.21.0","20.21.1","20.22.0","20.23.0","20.23.1","20.24.0","20.24.1","20.24.2","20.24.3","20.24.4","20.24.5","20.24.6","20.24.7","20.25.0","20.25.1","20.25.2","20.25.3","20.26.0","20.26.1","20.26.2","20.26.3","20.26.4","20.26.5","20.26.6","20.27.0","20.27.1","20.28.0","20.28.1","20.29.0","20.29.1","20.29.2","20.29.3","20.3.0","20.3.1","20.30.0","20.31.0","20.31.1","20.31.2","20.32.0","20.33.0","20.33.1","20.34.0","20.35.0","20.35.1","20.35.2","20.35.3","20.35.4","20.36.0","20.4.0","20.4.1","20.4.2","20.4.3","20.4.4","20.4.5","20.4.6","20.4.7","20.5.0","20.6.0","20.7.0","20.7.1","20.7.2","20.8.0","20.8.1","20.9.0"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/virtualenv/PYSEC-2026-2009.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L"}]}