CVE-2026-59739
Received
Received - Intake
Information Disclosure via SetWatches Reconnect Replay in Apache ZooKeeper
Vulnerability report for CVE-2026-59739, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-16
Last updated on: 2026-09-16
Assigner: Apache Software Foundation
Description
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| apache | zookeeper | 3.9.6 |
| apache | zookeeper | 3.8.7 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-862 | The product does not perform an authorization check when an actor attempts to access a resource or perform an action. |
