BREW-CLOUDISCOVERY-CVE-2… (PYSEC-2026-4011)

Vulnerability from osv_homebrew – Published: 2026-09-30 21:05 – Updated: 2026-09-30 21:05 – Source website
VLAI
Summary
Downloaded seed wheels (pip/setuptools) are not integrity-checked before use
Details

download_wheel() runs pip download and hands the result straight to the seeder, with nothing checking the bytes it gets back. The embedded pip and setuptools wheels carry a BUNDLE_SHA256 that virtualenv checks on every load, but a wheel fetched over the network for the periodic-update feature or the --download flag had no equivalent verification.

A compromised index, a stale mirror, or a MITM'd download (when TLS is intercepted, e.g. via a misconfigured or malicious CA) could substitute a different wheel under the same distribution/version/filename, and virtualenv would cache and seed it into every environment created afterward with no warning.

Fixed in 21.7.12 by computing the downloaded wheel's sha256 and comparing it against the digest PyPI's public JSON API reports for that exact release, independent of which index actually served the file. The check is skipped, not treated as failure, when a custom index (PIP_INDEX_URL, PIP_EXTRA_INDEX_URL, PIP_INDEX) is configured, since a private index can legitimately serve a different, intentionally rebuilt wheel.

References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "virtualenv",
        "resource_purl": "pkg:pypi/virtualenv@20.31.2",
        "upstream_fixed_in": "21.7.12"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "cloudiscovery",
        "purl": "pkg:brew/cloudiscovery"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.4.4_4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/virtualenv@20.31.2",
        "name": "virtualenv",
        "resource": "virtualenv",
        "strategy": "registry",
        "subject_version": "20.31.2"
      }
    ]
  },
  "details": "`download_wheel()` runs `pip download` and hands the result straight to the\nseeder, with nothing checking the bytes it gets back. The embedded pip and\nsetuptools wheels carry a `BUNDLE_SHA256` that virtualenv checks on every load,\nbut a wheel fetched over the network for the periodic-update feature or the\n`--download` flag had no equivalent verification.\n\nA compromised index, a stale mirror, or a MITM\u0027d download (when TLS is\nintercepted, e.g. via a misconfigured or malicious CA) could substitute a\ndifferent wheel under the same distribution/version/filename, and virtualenv\nwould cache and seed it into every environment created afterward with no\nwarning.\n\nFixed in 21.7.12 by computing the downloaded wheel\u0027s sha256 and comparing it\nagainst the digest PyPI\u0027s public JSON API reports for that exact release,\nindependent of which index actually served the file. The check is skipped, not\ntreated as failure, when a custom index (`PIP_INDEX_URL`,\n`PIP_EXTRA_INDEX_URL`, `PIP_INDEX`) is configured, since a private index can\nlegitimately serve a different, intentionally rebuilt wheel.\n",
  "id": "BREW-cloudiscovery-CVE-2026-102930",
  "modified": "2026-09-30T21:05:15Z",
  "published": "2026-09-30T21:05:15Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-94p9-xgh2-xp45"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/pull/3251"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pypa/virtualenv/commit/a01ed3e2f239d6ab1fce62c5c7664ccf268fff6d"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/releases/tag/21.7.12"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pypa/virtualenv"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/virtualenv"
    }
  ],
  "schema_version": "1.7.3",
  "summary": "Downloaded seed wheels (pip/setuptools) are not integrity-checked before use",
  "upstream": [
    "PYSEC-2026-4011",
    "CVE-2026-102930",
    "GHSA-94p9-xgh2-xp45"
  ]
}



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