---
id: CVE-2026-77791
title: >-
  Uncontrolled Resource Consumption vulnerability in Apache Tomcat during
  sending of WebSocket close message enabled a DoS attack.




  This issue affects Apache Tomcat: from 11.0.0-M5 through 11.0.25, from 10.1.8
  through 10.1.59, from 9.0.7…
summary: >-
  Uncontrolled Resource Consumption vulnerability in Apache Tomcat during
  sending of WebSocket close message enabled a DoS attack.




  This issue affects Apache Tomcat: from 11.0.0-M5 through 11.0.25, from 10.1.8
  through 10.1.59, from 9.0.7…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
vendor: Apache Software Foundation
product: Apache Tomcat
affected:
  - apache_tomcat >= 11.0.0-M5 <= 11.0.25
  - apache_tomcat >= 10.1.8 <= 10.1.59
  - apache_tomcat >= 9.0.74 <= 9.0.121
  - apache_tomcat >= 8.5.88 <= 8.5.100
published: '2026-09-23'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T19:19:19.043'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77791'
references:
  - url: 'https://lists.apache.org/thread/mb1pjjooqytrl6hbvbt3rw1lqwlon4cz'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/23/24'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-23T12:44:33.453302Z'
ingestedAt: '2026-09-23T12:24:04.182Z'
---

## Overview

Uncontrolled Resource Consumption vulnerability in Apache Tomcat during sending of WebSocket close message enabled a DoS attack.



This issue affects Apache Tomcat: from 11.0.0-M5 through 11.0.25, from 10.1.8 through 10.1.59, from 9.0.74 through 9.0.121.



The following versions were EOL at the time the CVE was created but are 
known to be affected: from 8.5.88 through 8.5.100. Other unsupported versions may also be affected.




Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.