Bug 2535097 (CVE-2026-59969) - CVE-2026-59969 zookeeper: Apache ZooKeeper: Improper certificate validation in FIPS mode allows quorum compromise
Summary: CVE-2026-59969 zookeeper: Apache ZooKeeper: Improper certificate validation i...
Keywords:
Status: NEW
Alias: CVE-2026-59969
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2542323 2542324 2542325
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-16 09:49 UTC by OSIDB Bzimport
Modified: 2026-09-28 06:30 UTC (History)
53 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-16 09:49:46 UTC 
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.
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