{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": [
              "cpe:2.3:a:apache:tomcat:11.0.0:milestone20:*:*:*:*:*:*",
              "cpe:2.3:a:apache:tomcat:11.0.0:milestone21:*:*:*:*:*:*",
              "cpe:2.3:a:apache:tomcat:11.0.0:milestone22:*:*:*:*:*:*",
              "cpe:2.3:a:apache:tomcat:11.0.0:milestone23:*:*:*:*:*:*",
              "cpe:2.3:a:apache:tomcat:11.0.0:milestone24:*:*:*:*:*:*",
              "cpe:2.3:a:apache:tomcat:11.0.0:milestone25:*:*:*:*:*:*",
              "cpe:2.3:a:apache:tomcat:11.0.0:milestone26:*:*:*:*:*:*"
            ],
            "extracted_events": [
              {
                "introduced": "11.0.0-milestone20"
              },
              {
                "last_affected": "11.0.0-milestone20"
              },
              {
                "introduced": "11.0.0-milestone21"
              },
              {
                "last_affected": "11.0.0-milestone21"
              },
              {
                "introduced": "11.0.0-milestone22"
              },
              {
                "last_affected": "11.0.0-milestone22"
              },
              {
                "introduced": "11.0.0-milestone23"
              },
              {
                "last_affected": "11.0.0-milestone23"
              },
              {
                "introduced": "11.0.0-milestone24"
              },
              {
                "last_affected": "11.0.0-milestone24"
              },
              {
                "introduced": "11.0.0-milestone25"
              },
              {
                "last_affected": "11.0.0-milestone25"
              },
              {
                "introduced": "11.0.0-milestone26"
              },
              {
                "last_affected": "11.0.0-milestone26"
              }
            ],
            "source": "CPE_STRING"
          },
          "events": [
            {
              "introduced": "c400bf727cbc10198d3f52c29849d18660050b0c"
            },
            {
              "last_affected": "e9935d107776339a4a48cf4e32195a763fbf8379"
            }
          ],
          "repo": "https://github.com/apache/tomcat",
          "type": "GIT"
        }
      ],
      "versions": [
        "11.0.0-milestone20",
        "11.0.0-milestone21",
        "11.0.0-milestone22",
        "11.0.0-milestone23",
        "11.0.0-milestone24",
        "11.0.0-milestone25",
        "11.0.0-milestone26"
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "apache",
    "cwe_ids": [
      "CWE-400"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66299.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "11.0.0-M20"
          },
          {
            "last_affected": "11.0.24"
          },
          {
            "introduced": "10.1.24"
          },
          {
            "last_affected": "10.1.57"
          },
          {
            "introduced": "9.0.89"
          },
          {
            "last_affected": "9.0.120"
          }
        ],
        "source": "AFFECTED_FIELD"
      },
      {
        "extracted_events": [
          {
            "introduced": "11.0.0-M20"
          },
          {
            "fixed": "11.0.24"
          },
          {
            "introduced": "10.1.24"
          },
          {
            "fixed": "10.1.57"
          },
          {
            "introduced": "9.0.89"
          },
          {
            "fixed": "9.0.120"
          }
        ],
        "source": "DESCRIPTION"
      }
    ]
  },
  "details": "Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example.\n\nThis issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web application are not affected by this issue.\n\nUsers are recommended to remove the examples web application or to upgrade to version 11.0.25, 10.1.58 or 9.0.121 (when released), which fix the issue.",
  "id": "CVE-2026-66299",
  "modified": "2026-08-12T03:51:36.643117295Z",
  "published": "2026-07-28T14:29:05.810Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/28/25"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66299.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66299"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Apache Tomcat: DoS via WebSocket chat example"
}