GHSA-94P9-XGH2-XP45

Vulnerability from github – Published: 2026-09-30 23:54 – Updated: 2026-09-30 23:54
VLAI
Summary
virtualenv: 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 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. Fix: https://github.com/pypa/virtualenv/pull/3251

Severity
7.7 (High)
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 21.7.11"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "virtualenv"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "21.7.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-102930"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-494"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-30T23:54:13Z",
    "nvd_published_at": "2026-09-29T21:17:18Z",
    "severity": "HIGH"
  },
  "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.\n\nA compromised index, a stale mirror, or a MITM\u0027d 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.\n\nFixed by computing the downloaded wheel\u0027s sha256 and comparing it against the digest PyPI\u0027s 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. Fix: https://github.com/pypa/virtualenv/pull/3251",
  "id": "GHSA-94p9-xgh2-xp45",
  "modified": "2026-09-30T23:54:13Z",
  "published": "2026-09-30T23:54:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/security/advisories/GHSA-94p9-xgh2-xp45"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102930"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/pull/3251"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/commit/a01ed3e2f239d6ab1fce62c5c7664ccf268fff6d"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/virtualenv/PYSEC-2026-4011.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pypa/virtualenv"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/virtualenv/releases/tag/21.7.12"
    },
    {
      "type": "WEB",
      "url": "https://pypi.org/project/virtualenv"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "virtualenv: Downloaded seed wheels (pip/setuptools) are not integrity-checked before use"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.