Bug 2535093 (CVE-2026-59739) - CVE-2026-59739 zookeeper: Apache ZooKeeper: Information disclosure via SetWatches reconnect replay
Summary: CVE-2026-59739 zookeeper: Apache ZooKeeper: Information disclosure via SetWat...
Keywords:
Status: NEW
Alias: CVE-2026-59739
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2542317 2542318 2542319
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-16 09:46 UTC by OSIDB Bzimport
Modified: 2026-09-28 06:24 UTC (History)
53 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-16 09:46:04 UTC 
Information disclosure via SetWatches reconnect replay in Apache ZooKeeper due to missing ACL check. An attacker can discover ACL-restricted paths by registering exists-watches on non-existent paths, then reconnecting after the paths are created with restricted ACLs. Issue is caused by incomplete fix for CVE-2024-23944 (ZOOKEEPER-4799). The fix added ACL checking to WatchManager.triggerWatch(). However, DataTree.setWatches() — the SetWatches/SetWatches2 reconnect replay handler — still calls watcher.process(event) with null ACL, bypassing the check entirely. It's important to note that only the path is exposed by this vulnerability, not the data of znode, but since znode path can contain sensitive information like user name or login ID, this issue is potentially critical.

Users are recommended to upgrade to version 3.9.6, 3.8.7 which fixes the issue.
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