{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "source": "REFERENCES"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "640dd2383a1a2fb1a10e5222d50ebc0b22a61bd7"
            }
          ],
          "repo": "https://github.com/mongodb/mongo-python-driver",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-v4x9-3549-crwv"
  ],
  "database_specific": {
    "cna_assigner": "mongodb",
    "cwe_ids": [
      "CWE-190"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/96xxx/CVE-2026-96749.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "1.9.0"
          },
          {
            "fixed": "4.18.2"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "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.",
  "id": "CVE-2026-96749",
  "modified": "2026-09-27T03:30:31.932310508Z",
  "published": "2026-09-24T18:18:13.077Z",
  "references": [
    {
      "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": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/96xxx/CVE-2026-96749.json"
    },
    {
      "type": "ADVISORY",
      "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"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "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": "Heap out-of-bounds write via signed size overflow in BSON document encoding"
}