Vulnerability in Apache Software Foundation Apache ZooKeeper

[ Description ]Official 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.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund13 Oct 2026WID-SEC-2026-3908

  IBM SPSS: Multiple vulnerabilities Translated from German

  CVE-2026-59969CVE-2026-84501CVE-2026-79993+2 more CVEs

[ References ]References

• lists.apache.org/thread/qf9kwsgtgbgtvwls6f41281846xg0rssvendor-advisory