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 ↗

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

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

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