CVE-2026-59969Apache ZooKeeper: Improper validation of certificate with host mismatch in FIPS mode
Updated under an hour ago ()
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It affects Apache Software Foundation Apache ZooKeeper and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Weakness (CWE)
- CWE-297
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- apache
- NVD analysis
- Analyzed
- Record last updated
- Sep 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Apache Software Foundation Apache ZooKeeper apache_software_foundation:apache_zookeeper (from the name) | from 3.9.0 through 3.9.5; from 3.8.0 through 3.8.6 | CNA record |
apache zookeeper apache:zookeeper | from 3.8.0 before 3.8.7; from 3.9.0 before 3.9.6 | NVD |
References
- https://lists.apache.org/thread/qf9kwsgtgbgtvwls6f41281846xg0rssvendor-advisory, mailing-list
- http://www.openwall.com/lists/oss-security/2026/09/15/4mailing-list, third-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.