UBUNTU-CVE-2026-81624 (CVE-2026-81624)

Vulnerability from osv_ubuntu – Published: 2026-08-31 09:17 – Updated: 2026-09-02 16:28 – Source website
VLAI
Details

Undertow is a flexible performant web server used in JBoss EAP and WildFly. A flaw was found in how Undertow handles WebSocket connections. Specifically, certain configuration limits like message buffer sizes and session timeouts cannot be adjusted and default to being unlimited. This allows a remote attacker to send large amounts of data or maintain connections indefinitely, potentially crashing the server by exhausting its memory or other resources.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libundertow-java",
            "binary_version": "1.3.16-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "undertow",
        "purl": "pkg:deb/ubuntu/undertow@1.3.16-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.3.4-1",
        "1.3.5-1",
        "1.3.7-1",
        "1.3.11-1",
        "1.3.16-1",
        "1.3.16-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libundertow-java",
            "binary_version": "1.4.23-3ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "undertow",
        "purl": "pkg:deb/ubuntu/undertow@1.4.23-3ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.4.20-1",
        "1.4.21-1",
        "1.4.22-1",
        "1.4.23-1",
        "1.4.23-2build1",
        "1.4.23-3",
        "1.4.23-3ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libundertow-java",
            "binary_version": "2.0.29-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "undertow",
        "purl": "pkg:deb/ubuntu/undertow@2.0.29-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.23-1",
        "2.0.27-1",
        "2.0.28-1",
        "2.0.29-1",
        "2.0.29-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libundertow-java",
            "binary_version": "2.2.16-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "undertow",
        "purl": "pkg:deb/ubuntu/undertow@2.2.16-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.2.8-1",
        "2.2.12-1",
        "2.2.13-1",
        "2.2.14-1",
        "2.2.16-1",
        "2.2.16-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libundertow-java",
            "binary_version": "2.3.8-2ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "undertow",
        "purl": "pkg:deb/ubuntu/undertow@2.3.8-2ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.3.8-2",
        "2.3.8-2ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libundertow-java",
            "binary_version": "2.3.20-1ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "undertow",
        "purl": "pkg:deb/ubuntu/undertow@2.3.20-1ubuntu1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.3.18-2",
        "2.3.20-1",
        "2.3.20-1ubuntu1"
      ]
    }
  ],
  "aliases": [],
  "details": "Undertow is a flexible performant web server used in JBoss EAP and WildFly. A flaw was found in how Undertow handles WebSocket connections. Specifically, certain configuration limits like message buffer sizes and session timeouts cannot be adjusted and default to being unlimited. This allows a remote attacker to send large amounts of data or maintain connections indefinitely, potentially crashing the server by exhausting its memory or other resources.",
  "id": "UBUNTU-CVE-2026-81624",
  "modified": "2026-09-02T16:28:28Z",
  "published": "2026-08-31T09:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-81624"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-81624"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2524868"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2026-81624"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-81624"
  ]
}



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