{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "1.4.0"
              },
              {
                "fixed": "1.11.1"
              }
            ],
            "source": [
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "e5d4262b07b3e1026c57647b281dccfababea13b"
            },
            {
              "fixed": "40a1b8fc924694a0125bbaa7fee101fa43feeb52"
            },
            {
              "fixed": "ae3520dfdbfab115c638f8c7f6f6b805db34e1ab"
            }
          ],
          "repo": "https://github.com/mtrudel/bandit",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-9q9q-324x-93r2"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39803.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "903e209a521bc216b9f9065c01ae9a0cac2d5a10"
          },
          {
            "fixed": "ae3520dfdbfab115c638f8c7f6f6b805db34e1ab"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows unauthenticated remote denial of service via memory exhaustion.\n\nThe chunked clause of 'Elixir.Bandit.HTTP1.Socket':read_data/2 in lib/bandit/http1/socket.ex ignores the caller-supplied :length option when reading HTTP/1 chunked request bodies. Instead of capping the accumulated body at the configured limit (e.g. Plug.Parsers' default 8 MB), do_read_chunked_data!/5 buffers every received chunk into an iolist unconditionally and materializes the entire body as a single binary. The function always returns {:ok, body, ...}, so callers cannot interpose a 413 response.\n\nBecause Plug.Parsers runs before routing and authentication in the standard Phoenix endpoint, an unauthenticated attacker needs no valid route or credentials. Sending a single Transfer-Encoding: chunked POST request with an arbitrarily large body to any path causes the BEAM process to exhaust available memory and be terminated by the OS OOM killer.\n\nThe content-length path in the same function correctly enforces the limit and is not affected.\n\nThis issue affects bandit: from 1.4.0 before 1.11.1.",
  "id": "CVE-2026-39803",
  "modified": "2026-07-08T05:36:43.356261356Z",
  "published": "2026-05-13T13:36:09.648Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-39803.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-39803"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39803.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-9q9q-324x-93r2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-39803"
    },
    {
      "type": "FIX",
      "url": "https://github.com/mtrudel/bandit/commit/ae3520dfdbfab115c638f8c7f6f6b805db34e1ab"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mtrudel/bandit"
    }
  ],
  "schema_version": "1.7.5",
  "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": "HTTP/1 chunked body reader ignores length cap in bandit"
}