CVE-2026-22702: Virtualenv Virtualenv Has TOCTOU Vulnerabilities Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-597g-3phw-6986",
  "modified" : "2026-01-13T18:45:57Z",
  "published" : "2026-01-13T18:45:57Z",
  "aliases" : [ "CVE-2026-22702" ],
  "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",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "virtualenv"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "20.36.1"
      } ]
    } ]
  } ],
  "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" : "WEB",
    "url" : "https://github.com/pypa/virtualenv/commit/dec4cec5d16edaf83a00a658f32d1e032661cebc"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pypa/virtualenv"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-362", "CWE-59" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-13T18:45:57Z",
    "nvd_published_at" : "2026-01-10T07:16:02Z"
  }
}