PYSEC-2026-4296

Vulnerability from pysec - Published: 2026-10-15 10:22 - Updated: 2026-10-15 14:38
VLAI
Details

An integer overflow in the BSON document encoding component of the MongoDB Python Driver's bundled native extension may occur when a single document is built from an unusually large amount of caller-supplied data. Size arithmetic is performed in a signed 32-bit type, and the guard meant to catch the overflow is written in a form whose behavior is not defined by the C language standard. A party with no privileges who can place a very large value into data that an application encodes may, depending on how the native extension was built, cause a write outside the bounds of an allocated buffer inside the application's own process.

Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5 (High)
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Impacted products
Name purl
pymongo pkg:pypi/pymongo
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pymongo",
        "purl": "pkg:pypi/pymongo"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.18.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.1pre",
        "0.1.2pre",
        "0.10",
        "0.10.1",
        "0.10.2",
        "0.10.3",
        "0.11",
        "0.11.1",
        "0.11.2",
        "0.11.3",
        "0.12",
        "0.13",
        "0.14",
        "0.14.1",
        "0.14.2",
        "0.15",
        "0.15.1",
        "0.15.2",
        "0.16",
        "0.1pre",
        "0.2pre",
        "0.3.1pre",
        "0.3pre",
        "0.4pre",
        "0.5.1pre",
        "0.5.2pre",
        "0.5.3pre",
        "0.5pre",
        "0.6",
        "0.7",
        "0.7.1",
        "0.7.2",
        "0.8",
        "0.8.1",
        "0.9",
        "0.9.1",
        "0.9.2",
        "0.9.3",
        "0.9.4",
        "0.9.5",
        "0.9.6",
        "0.9.7",
        "1.0",
        "1.1",
        "1.1.1",
        "1.1.2",
        "1.10",
        "1.10.1",
        "1.11",
        "1.2",
        "1.2.1",
        "1.3",
        "1.4",
        "1.5",
        "1.5.1",
        "1.5.2",
        "1.6",
        "1.7",
        "1.8",
        "1.8.1",
        "1.9",
        "2.0",
        "2.0.1",
        "2.1",
        "2.1.1",
        "2.2",
        "2.2.1",
        "2.3",
        "2.4",
        "2.4.1",
        "2.4.2",
        "2.5",
        "2.5.1",
        "2.5.2",
        "2.6",
        "2.6.1",
        "2.6.2",
        "2.6.3",
        "2.7",
        "2.7.1",
        "2.7.2",
        "2.8",
        "2.8.1",
        "2.9",
        "2.9.1",
        "2.9.2",
        "2.9.3",
        "2.9.4",
        "2.9.5",
        "3.0",
        "3.0.1",
        "3.0.2",
        "3.0.3",
        "3.1",
        "3.1.1",
        "3.10.0",
        "3.10.1",
        "3.11.0",
        "3.11.1",
        "3.11.2",
        "3.11.3",
        "3.11.4",
        "3.12.0",
        "3.12.1",
        "3.12.2",
        "3.12.3",
        "3.13.0",
        "3.2",
        "3.2.1",
        "3.2.2",
        "3.3.0",
        "3.3.1",
        "3.4.0",
        "3.5.0",
        "3.5.1",
        "3.6.0",
        "3.6.1",
        "3.7.0",
        "3.7.1",
        "3.7.2",
        "3.8.0",
        "3.9.0",
        "4.0",
        "4.0.1",
        "4.0.2",
        "4.1.0",
        "4.1.1",
        "4.10.0",
        "4.10.1",
        "4.11",
        "4.11.1",
        "4.11.2",
        "4.11.3",
        "4.12.0",
        "4.12.1",
        "4.13.0",
        "4.13.0.dev0",
        "4.13.1",
        "4.13.2",
        "4.14.0",
        "4.14.1",
        "4.15.0",
        "4.15.1",
        "4.15.2",
        "4.15.3",
        "4.15.4",
        "4.15.5",
        "4.16.0",
        "4.16.0.dev0",
        "4.17.0",
        "4.18.0",
        "4.18.1",
        "4.2.0",
        "4.3.2",
        "4.3.3",
        "4.4.0",
        "4.4.0b0",
        "4.4.1",
        "4.5.0",
        "4.6.0",
        "4.6.1",
        "4.6.2",
        "4.6.3",
        "4.7.0",
        "4.7.1",
        "4.7.2",
        "4.7.3",
        "4.8.0",
        "4.8.0b0",
        "4.9",
        "4.9.1",
        "4.9.2"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-96749",
    "GHSA-v4x9-3549-crwv"
  ],
  "details": "An integer overflow in the BSON document encoding component of the MongoDB Python Driver\u0027s bundled native extension may occur when a single document is built from an unusually large amount of caller-supplied data. Size arithmetic is performed in a signed 32-bit type, and the guard meant to catch the overflow is written in a form whose behavior is not defined by the C language standard. A party with no privileges who can place a very large value into data that an application encodes may, depending on how the native extension was built, cause a write outside the bounds of an allocated buffer inside the application\u0027s own process.",
  "id": "PYSEC-2026-4296",
  "modified": "2026-10-15T14:38:08.667294Z",
  "published": "2026-10-15T10:22:46.249312Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/mongodb/mongo-python-driver/security/advisories/GHSA-v4x9-3549-crwv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-96749"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mongodb/mongo-python-driver/pull/3066"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mongodb/mongo-python-driver/commit/640dd2383a1a2fb1a10e5222d50ebc0b22a61bd7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mongodb/mongo-python-driver/commit/6ab44be0e97c9d1d5a23725c4978fb25f3249485"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mongodb/mongo-python-driver"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mongodb/mongo-python-driver/blob/4.18.2/doc/changelog.rst"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mongodb/mongo-python-driver/releases/tag/4.18.2"
    },
    {
      "type": "WEB",
      "url": "https://www.mongodb.com/community/forums/t/pymongo-4-18-2-released/343732"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/pymongo"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-v4x9-3549-crwv"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "PyMongo: PYTHON-5996 Heap out-of-bounds write via signed size overflow in BSON document encoding"
}



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