---
id: CVE-2026-78383
title: >-
  Allocation of resources without limits or throttling vulnerability in Apache
  Tomcat allows an unauthenticated AJP request to pin an AJP processing thread
  leading to denial of service.




  This issue affects Apache Tomcat: from 11.0.0-M1 t…
summary: >-
  Allocation of resources without limits or throttling vulnerability in Apache
  Tomcat allows an unauthenticated AJP request to pin an AJP processing thread
  leading to denial of service.




  This issue affects Apache Tomcat: from 11.0.0-M1 t…
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-770
vendor: Apache Software Foundation
product: Apache Tomcat
affected:
  - apache_tomcat >= 11.0.0-M1 <= 11.0.25
  - apache_tomcat >= 10.1.0-M1 <= 10.1.59
  - apache_tomcat >= 9.0.0.M1 <= 9.0.121
  - apache_tomcat >= 8.5.0 <= 8.5.100
  - apache_tomcat >= 7.0.0 <= 7.0.109
published: '2026-09-23'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T19:19:21.470'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-78383'
references:
  - url: 'https://lists.apache.org/thread/tyqcqk99g7ghgk22641vf67vghcyswnw'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/23/25'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-23T15:44:38.108504Z'
ingestedAt: '2026-09-23T12:24:04.183Z'
epss: 0.00376
epssPercentile: 0.28858
---

## Overview

Allocation of resources without limits or throttling vulnerability in Apache Tomcat allows an unauthenticated AJP request to pin an AJP processing thread leading to denial of service.



This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121.



The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. 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.