Apache ZooKeeper quorum TLS fails to enforce peer hostname verification in FIPS-mode deployments. When sslQuorum=true, zookeeper.fips-mode=true, ssl.quorum.hostnameVerification=true, and ssl.quorum.clientHostnameVerification=true are enabled, the Java SSLSocket quorum path accepts a CA-trusted peer certificate whose SAN does not match the connected host. A malicious or misissued peer certificate can therefore join quorum traffic, participate in leader election, and enter replication flows. Users are recommended to upgrade to version 3.8.7 or 3.9.6, which fixes the issue.
History

Mon, 28 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-295
References
Metrics threat_severity

None

threat_severity

Important


Fri, 18 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:apache:zookeeper:*:*:*:*:*:*:*:*

Thu, 17 Sep 2026 21:15:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache zookeeper
Vendors & Products Apache
Apache zookeeper

Thu, 17 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 16 Sep 2026 11:30:00 +0000

Type Values Removed Values Added
References

Wed, 16 Sep 2026 09:45:00 +0000

Type Values Removed Values Added
Description Apache ZooKeeper quorum TLS fails to enforce peer hostname verification in FIPS-mode deployments. When sslQuorum=true, zookeeper.fips-mode=true, ssl.quorum.hostnameVerification=true, and ssl.quorum.clientHostnameVerification=true are enabled, the Java SSLSocket quorum path accepts a CA-trusted peer certificate whose SAN does not match the connected host. A malicious or misissued peer certificate can therefore join quorum traffic, participate in leader election, and enter replication flows. Users are recommended to upgrade to version 3.8.7 or 3.9.6, which fixes the issue.
Title Apache ZooKeeper: Improper validation of certificate with host mismatch in FIPS mode
Weaknesses CWE-297
References

cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published: 2026-09-16T09:27:00.726Z

Updated: 2026-09-17T19:17:01.444Z

Reserved: 2026-07-07T18:50:40.959Z

Link: CVE-2026-59969

cve-icon Vulnrichment

Updated: 2026-09-17T19:16:56.939Z

cve-icon NVD

Status : Analyzed

Published: 2026-09-16T10:16:51.220

Modified: 2026-09-18T14:31:23.357

Link: CVE-2026-59969

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-16T09:27:00Z

Links: CVE-2026-59969 - Bugzilla