CVE & CISA-KEV Catalog

CVE-2026-59969

HIGH
7.5
CVSS v3
NVD

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.

How to fix

Remediation Available
zookeeperNVD
Affected:>= 3.8.0, < 3.8.7Fixed in:3.8.7CVE-2026-59969derived from NVD
Affected:>= 3.9.0, < 3.9.6Fixed in:3.9.6CVE-2026-59969derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityHigh
AvailabilityNone

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

Exploit Intelligence

EPSS data unavailable for this CVE.

References

Vendor Advisory1
Third-Party Advisory1

Related Vulnerabilities

Other CWE-297 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2014-3522Medium4.05.6%-Fix
CVE-2018-10936High8.12.9%-Fix
CVE-2024-2466Medium6.51.3%-Fix
CVE-2020-1887Critical9.11.3%-Fix
CVE-2020-14387High7.41.1%-Fix
CVE-2020-15260Medium6.81.0%-Fix

Common questions

How do I fix CVE-2026-59969?

Upgrade zookeeper to 3.8.7 or later.

How severe is CVE-2026-59969?

CVE-2026-59969 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-59969 affect?

Published advisories record a fix for zookeeper (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-18.