{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0.5.0"
              },
              {
                "fixed": "1.11.0"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "102adfd56bd4aacd39469a5582104377618abc9f"
            },
            {
              "fixed": "e62619895d0d2584d7ffa57d43ef6f72437dfaff"
            },
            {
              "fixed": "21612c7c7b1ce43eccd36d3af3a2299d23513667"
            }
          ],
          "repo": "https://github.com/mtrudel/bandit",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-pf94-94m9-536p"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42786.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "8909391f486d42138c5308410bc5ea49a65f4d46"
          },
          {
            "fixed": "21612c7c7b1ce43eccd36d3af3a2299d23513667"
          }
        ],
        "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 fragment reassembly path in 'Elixir.Bandit.WebSocket.Connection':handle_frame/3 in lib/bandit/websocket/connection.ex appends every incoming Continuation{fin: false} frame's payload to a per-connection iolist with no cumulative size cap. The existing max_frame_size option only bounds individual frames; a peer that streams an unbounded number of continuation frames without ever setting fin=1 grows BEAM heap linearly until the OS or a supervisor kills the process.\n\nBecause the accumulation happens before WebSock.handle_in/2 is called, the application has no opportunity to interpose a size check. Phoenix Channels and LiveView both run over WebSock on Bandit, so a stock Phoenix application exposes this surface as soon as it accepts socket connections.\n\nThis issue affects bandit: from 0.5.0 before 1.11.0.",
  "id": "CVE-2026-42786",
  "modified": "2026-07-08T05:37:33.346596029Z",
  "published": "2026-05-01T20:34:17.014Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-42786.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-42786"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42786.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-pf94-94m9-536p"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42786"
    },
    {
      "type": "FIX",
      "url": "https://github.com/mtrudel/bandit/commit/21612c7c7b1ce43eccd36d3af3a2299d23513667"
    },
    {
      "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": "WebSocket fragmented message reassembly unbounded in bandit"
}