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BREW-PYTHON@3.9-CVE-2026-13346 (PYSEC-2026-3721)

Vulnerability from osv_homebrew – Published: 2026-08-23 21:32 – Updated: 2026-09-10 20:33 – Source website
VLAI
Summary
pip would incorrectly handle doubly-encoded package URLs from indexes
Details

pip would incorrectly handle doubly-encoded package URLs from indexes allowing for files to be installed to arbitrary locations on disk even when installing wheels.

This vulnerability requires downloading or installing a package from a malicious package index to succeed, malicious packages alone are not able to exploit this vulnerability. Note that this vulnerability only materially impacts users running pip download with the --only-binary option as installing source distributions from an untrusted index is already an unsafe operation that executes code during install time.

Severity
5.6 (Medium)
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "pip",
        "resource_purl": "pkg:pypi/pip@25.3",
        "upstream_fixed_in": "26.2.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "python@3.9",
        "purl": "pkg:brew/python%403.9"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/pip@25.3",
        "name": "pip",
        "resource": "pip",
        "strategy": "registry",
        "subject_version": "25.3"
      }
    ]
  },
  "details": "pip would incorrectly handle doubly-encoded package URLs from indexes allowing for files to be installed to arbitrary locations on disk even when installing wheels.\n\nThis vulnerability requires downloading or installing a package from a malicious package index to succeed, malicious packages alone are not able to exploit this vulnerability. Note that this vulnerability only materially impacts users running `pip download` with the `--only-binary` option as installing source distributions from an untrusted index is already an unsafe operation that executes code during install time.",
  "id": "BREW-python@3.9-CVE-2026-13346",
  "modified": "2026-09-10T20:33:57Z",
  "published": "2026-08-23T21:32:49Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-13346"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/pip/pull/14110"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/pip/commit/10dfb6b9005484578b386f64b9f36982e3dc6679"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/pip/PYSEC-2026-3721.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pypa/pip"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/L2BNQGGVQCEV7DROOORQ7WFKKFF2OOQX"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/29/7"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "pip would incorrectly handle doubly-encoded package URLs from indexes",
  "upstream": [
    "PYSEC-2026-3721",
    "CVE-2026-13346",
    "GHSA-qwm4-qh6w-59xr"
  ]
}



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