CVE-2026-100300

Improper handling of exceptional conditions in the quota subsystem of Apache ZooKeeper allows an attacker able to write under the /zookeeper/quota subtree — unauthenticated on default deployments, where that subtree is world-writable — to crash the server's critical request-processing thread and render the on-disk data directory permanently unbootable.

This issue affects Apache ZooKeeper up to and including 3.9.6. Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue.