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Fencer Vulns
high 7.5

CVE-2026-59969 json

Apache ZooKeeper: Improper validation of certificate with host mismatch in FIPS mode

published 2026-09-16 54 d ago modified 2026-09-19 51 d ago also BIT-zookeeper-2026-59969 , EUVD-2026-80331

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 26%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami zookeeper 3.8.7, 3.9.6
  • apache zookeeper 3.8.7, 3.9.6
  • zookeeper Debian 14 3.9.6-1

debian advisories DEBIAN-CVE-2026-59969

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-59969 updated cvss 9.0

zookeeper: Apache ZooKeeper: Improper certificate validation in FIPS mode allows quorum compromise

  • Red Hat AMQ Broker 7 parent, zookeeper, zookeeper-jute Red Hat build of Apache Camel for Spring Boot 4 flink-shaded-zookeeper-3, flink-shaded-zookeeper-parent Red Hat JBoss Enterprise Application Platform Expansion Pack parent, zookeeper Red Hat Offline Knowledge Portal offline-knowledge-portal/rhokp-rhel9
    affected: workaround, no fix available “Update to Apache ZooKeeper 3.8.7, 3.9.6, or later. As a workaround, disable FIPS mode if not required by compliance policies.”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-modelmesh-rhel9, rhoai/odh-spark-operator-rhel9, rhoai/odh-th06-cpu-torch210-py312-rhel9, rhoai/odh-th06-cpu-torch291-py312-rhel9, rhoai/odh-th06-rocm64-torch291-py312-rhel9, rhoai/odh-th06-cuda130-torch210-py312-rhel9, +1 more
    affected: workaround, no fix available, no fix planned “Update to Apache ZooKeeper 3.8.7, 3.9.6, or later. As a workaround, disable FIPS mode if not required by compliance policies.”
  • Red Hat JBoss Enterprise Application Platform 8.1
    fixed: vendor fix “Update to Apache ZooKeeper 3.8.7, 3.9.6, or later. As a workaround, disable FIPS mode if not required by compliance policies.” RHSA-2026:95221
  • Red Hat build of Apache Camel 4 for Quarkus 3 flink-shaded-zookeeper-3
    not affected: component not present
  • Red Hat Fuse 7 zookeeper, zookeeper-jute, camel-zookeeper, camel-zookeeper-master, camel-zookeeper-starter, flink-shaded-zookeeper-3, +8 more
    not affected: vulnerable code not in execute path
  • Red Hat JBoss Enterprise Application Platform 8 parent, zookeeper
    not affected: component not present
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-th-torch-cpu-py312-rhel9, rhoai/odh-th-torch-cuda-py312-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat OpenStack Platform 13 (Queens) puppet-zookeeper Red Hat OpenStack Platform 16.2 puppet-zookeeper
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
52 d ago

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
bitnami zookeeper
>=3.8.0, <3.8.7
>=3.9.0, <3.9.6
3.8.7
3.9.6

Affected products

  • Apache Software Foundation Apache ZooKeeper

Classification

Weakness
  • CWE-297 Improper Validation of Certificate with Host Mismatch

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.