{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-65623",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-65623",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-07-24T16:32:24.923Z",
    "updatedAt": "2026-07-25T04:16:42.726Z",
    "importedAt": "2026-10-24T01:58:25.636Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "Quadratic CPU blow-up reassembling fragmented WebSocket messages in Bandit",
      "summary": "Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly.\n\nThe size guard 'Elixir.Bandit.WebSocket.Connection':oversize_message?/2 called from handle_frame/3 in lib/bandit/websocket/connection.ex appends each non-final continuation frame to a left-nested iolist and then re-measures the entire accumulated buffer with IO.iodata_length/1 on every frame. Because the buffer grows by one element per frame and is fully re-traversed each time, reassembly work is quadratic (O(n^2)) in the number of continuation frames.\n\nThe max_fragmented_message_size limit (default 8 MB) bounds total bytes but not frame count, and each frame can carry as little as one payload byte, so an attacker can send millions of tiny continuation frames using modest bandwidth to pin a CPU core for minutes to hours. Many concurrent connections can starve the whole server of CPU, denying service to legitimate users. The WebSocket read timeout does not help, because it is an idle timeout evaluated between reads and cannot preempt the synchronous reassembly work spent inside a single callback.\n\nThis issue affects bandit: from 1.11.0 before 1.12.1.",
      "affected": [
        {
          "vendor": "mtrudel",
          "product": "bandit",
          "packageName": "bandit",
          "collectionURL": "https://repo.hex.pm",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "1.11.0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "1.12.1"
            }
          ]
        },
        {
          "vendor": "mtrudel",
          "product": "bandit",
          "packageName": "mtrudel/bandit",
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "21612c7c7b1ce43eccd36d3af3a2299d23513667",
              "status": "affected",
              "versionType": "git",
              "lessThan": "418ef7e906192a230ddba112f7a669c87b6b0e3a"
            }
          ]
        }
      ]
    }
  }
}