---
title: "CVE-2026-59969: Apache ZooKeeper - Authentication Bypass"
description: "Apache ZooKeeper contains a broken authentication caused by failure to enforce peer hostname verification in FIPS-mode quorum TLS, letting malicious peers join quorum traffic and participate in leader election, exploit requires specific TLS and FIPS mode settings enabled."
url: https://panop.io/threat-heartbeat/CVE-2026-59969/
---

# CVE-2026-59969 Apache ZooKeeper - Authentication Bypass

Apache ZooKeeper contains a broken authentication caused by failure to enforce peer hostname verification in FIPS-mode quorum TLS, letting malicious peers join quorum traffic and participate in leader election, exploit requires specific TLS and FIPS mode settings enabled.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.33% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-59969)

## Details

Type

Authentication Bypass

Impact

Broken Authentication

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Published

16 September 2026

Updated

15 October 2026

Weakness

[CWE-297](https://cwe.mitre.org/data/definitions/297.html)

## Vendor fix

Upgrade to version 3.8.7 or 3.9.6.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-59969](https://nvd.nist.gov/vuln/detail/CVE-2026-59969)
- [https://lists.apache.org/thread/qf9kwsgtgbgtvwls6f41281846xg0rss](https://lists.apache.org/thread/qf9kwsgtgbgtvwls6f41281846xg0rss)
- [http://www.openwall.com/lists/oss-security/2026/09/15/4](http://www.openwall.com/lists/oss-security/2026/09/15/4)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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