Fireware OS Pre-Authentication Integer Overflow in Access Portal Allows Out-of-Bounds Write

{
  "id": "5ad92648740874c33a8c8c5b27bc942f371ea76ef1cf9716ffe7235ce519935e",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-93866",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Fireware OS Pre-Authentication Integer Overflow in Access Portal Allows Out-of-Bounds Write",
    "summary": "An integer overflow vulnerability in the WebSocket connection handling used by WatchGuard Fireware OS's Access Portal allows a remote, unauthenticated attacker to write beyond the bounds of a heap buffer by sending a specially crafted request while the Access Portal feature is enabled.",
    "evidence": "cve:CVE-2026-93866",
    "products": [
      {
        "name": {
          "value": "Fireware OS",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "Fireware OS",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-93866",
      "aliases": [
        "CVE-2026-93866"
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "version": "4.0",
            "baseScore": 9.2,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
          }
        }
      ],
      "affected": [
        {
          "vendor": "WatchGuard",
          "product": "Fireware OS",
          "versions": [
            {
              "status": "affected",
              "version": "2025.1",
              "lessThan": "2026.4",
              "versionType": "custom"
            },
            {
              "status": "affected",
              "version": "12.0",
              "lessThan": "12.12.4",
              "versionType": "custom"
            }
          ],
          "platforms": [
            "Default"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "vendor": "WatchGuard",
          "product": "Fireware OS",
          "versions": [
            {
              "status": "affected",
              "version": "12.0",
              "lessThan": "12.5.22",
              "versionType": "custom"
            }
          ],
          "platforms": [
            "T15/T35"
          ],
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-27T15:52:27.871Z",
      "provider": "cve",
      "references": [
        "https://psirt.watchguard.com/CVE-2026-93866"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "5d1c2695-1a31-4499-88ae-e847036fd7e3",
          "shortName": "WatchGuard",
          "dateUpdated": "2026-10-27T15:52:27.871Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-93866",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 394438,
  "published_at": "2026-10-27T15:52:27.871+00:00"
}