{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "8.21.1"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "ae1de54330cef77e487548890fabfeb9aae1d83d"
            },
            {
              "fixed": "f197ac65140920bdcecdab74bfc69c2d7858e55d"
            }
          ],
          "repo": "https://github.com/websockets/ws",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62389.json"
  },
  "details": "ws before 8.21.1 contains a memory exhaustion vulnerability in lib/receiver.js where the fragment guard only triggers when fragment count reaches maxFragments, allowing attackers to exhaust memory by sending incomplete fragmented WebSocket messages. Attackers can send a text frame with FIN=0 followed by continuation frames without completing the sequence, causing each fragment to be stored as a separate Buffer object with significant overhead, enabling denial of service through heap exhaustion.",
  "id": "CVE-2026-62389",
  "modified": "2026-07-17T03:42:07.246269699Z",
  "published": "2026-07-15T17:04:26.250Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62389.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/websockets/ws/releases/tag/8.21.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-62389"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/ws-default-maxfragments-allows-memory-exhaustion-dos"
    },
    {
      "type": "FIX",
      "url": "https://github.com/websockets/ws/commit/f197ac65140920bdcecdab74bfc69c2d7858e55d"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/websockets/ws"
    },
    {
      "type": "ARTICLE",
      "url": "https://github.com/websockets/ws/issues/2331"
    }
  ],
  "schema_version": "1.8.0",
  "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": "ws \u003c 8.21.1 Default maxFragments Allows Memory Exhaustion DoS"
}