---
id: CVE-2026-100300
title: >-
  Apache ZooKeeper: Unauthenticated persistent denial of service via unvalidated
  quota-node data and paths crashing the transaction-apply thread
summary: >-
  Improper handling of exceptional conditions in the quota subsystem of Apache
  ZooKeeper allows an attacker able to write under the /zookeeper/quota subtree
  — unauthenticated on default deployments, where that subtree is world-writable
  — t…
severity: high
cvss: 8.7
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-755
vendor: Apache Software Foundation
product: 'org.apache.zookeeper:zookeeper'
affected:
  - 'org.apache.zookeeper:zookeeper >= 3.9.0 <= 3.9.6'
  - 'org.apache.zookeeper:zookeeper >= 3.8.0 <= 3.8.7'
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-11-04T14:35:55.242898Z'
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T15:18:55.306Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-100300'
references:
  - url: 'https://lists.apache.org/thread.html/09pgg7rcpzz44noxgtvpzstwt8fmvsb0'
tags:
  - cve.org
ingestedAt: '2026-11-05T21:36:00.430Z'
---

## Overview

Improper handling of exceptional conditions in the quota subsystem of Apache ZooKeeper allows an attacker able to write under the /zookeeper/quota subtree — unauthenticated on default deployments, where that subtree is world-writable — to crash the server's critical request-processing thread and render the on-disk data directory permanently unbootable.

This issue affects Apache ZooKeeper up to and including 3.9.6. Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue.

## Affected

- `org.apache.zookeeper:zookeeper >= 3.9.0 <= 3.9.6`
- `org.apache.zookeeper:zookeeper >= 3.8.0 <= 3.8.7`

## Remediation

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