Apache ZooKeeper: unauthenticated denial of service

Apache ZooKeeper

Apache ZooKeeper has an unauthenticated denial of service vulnerability

Do this now

Check the Apache ZooKeeper advisory for a fix and restrict network access to ZooKeeper meanwhile.

First seen: 3 Nov 2026
Last update: 3 Nov 2026, 20:19 UTC
Identifiers: CVE-2026-100300 ID not published yet
Source: news

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## Apache ZooKeeper: unauthenticated denial of service
Severity: unknown. Patch status: fix status unknown.
Affected: Apache ZooKeeper
Ids: CVE-2026-100300

Apache ZooKeeper has an unauthenticated denial of service vulnerability

## Steps
1. Search the repo, its CI and infra config for Apache ZooKeeper. If present, report the version in use and whether it's affected.
2. No source names a fix yet; check the vendor advisory. Until one ships: restrict network access to it.

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve("CVE-2026-100300") for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://seclists.org/oss-sec/2026/q4/486
https://pwned.coffee/i/apache-zookeeper-unauthenticated-denial-of-service-cve-2026-100300

Timeline

3 Nov 2026, 20:19 UTC
Fix status: no fix yet → unknown.
3 Nov 2026
First reported.

Receipt

Exploitation: No known exploitation
Score: No CVSS published yet: severity unknown.
Last checked: 4 Nov 2026, 08:18 UTC

Sources: KEV – CVE record – Vendor –

Sources

seclists.org: CVE-2026-100300: Apache ZooKeeper: Unauthenticated persistent denial of service via unvalidated quota-node data and paths crashing the transaction-apply thread

Totalone coffee