{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "3.13.14"
              },
              {
                "introduced": "3.14.0a1"
              },
              {
                "fixed": "3.14.5rc1"
              },
              {
                "introduced": "3.15.0a1"
              },
              {
                "fixed": "3.15.0b1"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "fd17997c3866d61e0e7bd8201b1d8f35b40a40bd"
            },
            {
              "introduced": "b092705907c758d4f9742028652c9802f9f03dd3"
            },
            {
              "fixed": "a68a9190498a16ab1a5c9012ef5a70df81a5b328"
            },
            {
              "introduced": "f31a89bb901067dd105b00cfa90523cf7ffdbbdd"
            },
            {
              "fixed": "f31a89bb901067dd105b00cfa90523cf7ffdbbdd"
            }
          ],
          "repo": "https://github.com/python/cpython",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "PSF",
    "cwe_ids": [
      "CWE-787"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3298.json"
  },
  "details": "The method \"sock_recvfrom_into()\" of \"asyncio.ProacterEventLoop\" (Windows only) was missing a boundary check for the data buffer when using nbytes parameter. This allowed for an out-of-bounds buffer write if data was larger than the buffer size. Non-Windows platforms are not affected.",
  "id": "CVE-2026-3298",
  "modified": "2026-08-04T11:31:23.702387279Z",
  "published": "2026-04-21T14:45:01.919Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3298.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/KWTPIQBOOOUNQP7UFSLBI437NJDFLA3F/"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-3298"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/python/cpython/issues/148808"
    },
    {
      "type": "FIX",
      "url": "https://github.com/python/cpython/commit/1274766d3c29007ab77245a72abbf8dce2a9db4d"
    },
    {
      "type": "FIX",
      "url": "https://github.com/python/cpython/commit/27522b7d6e6588f03e61099dd858cd5a9314e2f2"
    },
    {
      "type": "FIX",
      "url": "https://github.com/python/cpython/commit/95633d2aad4721e25e4dfd9f43dfb6e1edcbd741"
    },
    {
      "type": "FIX",
      "url": "https://github.com/python/cpython/pull/148809"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/python/cpython"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Out-of-bounds write in Windows asyncio.ProacterEventLoop.sock_recvfrom_into() when using nbytes"
}