{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "0"
                  },
                  {
                    "fixed": "3.14.4"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "fixed": "2d9c5c1062eff0034fb3ab120897a6c1b3ff7041"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "range": [
                  {
                    "fixed": "a555ab698e08e9baea7386d5b4c0761cb8956fdd"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "original_tag": "v3.14.4",
                "range": [
                  {
                    "fixed": "0c5e5e1c2256c2f46fa83912d01df7632c3b26cd"
                  }
                ],
                "source": "REFERENCES_TAG"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0c5e5e1c2256c2f46fa83912d01df7632c3b26cd"
            },
            {
              "fixed": "2d9c5c1062eff0034fb3ab120897a6c1b3ff7041"
            },
            {
              "fixed": "a555ab698e08e9baea7386d5b4c0761cb8956fdd"
            }
          ],
          "repo": "https://github.com/aio-libs/aiohttp",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-24c4-3p7v-29cm"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-400"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/128xxx/CVE-2026-128127.json"
  },
  "details": "AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, BodyPartReader.read_chunk() processing a multipart part with Content-Transfer-Encoding set to base64 keeps reading until the chunk length is a multiple of four without enforcing a byte limit. A short Content-Length or a long run of whitespace can cause one call to read the remaining body into memory before the size check or spin on the event loop. A remote attacker can send such a multipart request to a handler that reads multipart data and bypass client_max_size. This issue is fixed in version 3.14.4.",
  "id": "CVE-2026-128127",
  "modified": "2026-11-14T10:30:20.607153584Z",
  "published": "2026-11-13T20:30:19.198Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/128xxx/CVE-2026-128127.json"
    },
    {
      "type": "FIX",
      "url": "https://github.com/aio-libs/aiohttp/commit/2d9c5c1062eff0034fb3ab120897a6c1b3ff7041"
    },
    {
      "type": "FIX",
      "url": "https://github.com/aio-libs/aiohttp/commit/a555ab698e08e9baea7386d5b4c0761cb8956fdd"
    },
    {
      "type": "FIX",
      "url": "https://github.com/aio-libs/aiohttp/pull/13509"
    },
    {
      "type": "FIX",
      "url": "https://github.com/aio-libs/aiohttp/pull/13513"
    },
    {
      "type": "WEB",
      "url": "https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/aio-libs/aiohttp/security/advisories/GHSA-24c4-3p7v-29cm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-128127"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "AIOHTTP: Base64 multipart parts bypass client_max_size"
}