CVE-2026-59739
Published:September 16, 2026
Updated:September 22, 2026
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.
Affected Packages
https://github.com/apache/zookeeper.git (GITHUB):
Affected version(s) >=release-3.9.0-0 <release-3.9.6Fix Suggestion:
Update to version release-3.9.6https://github.com/apache/zookeeper.git (GITHUB):
Affected version(s) >=release-3.8.0-0 <release-3.8.7Fix Suggestion:
Update to version release-3.8.7org.apache.zookeeper:zookeeper (JAVA):
Affected version(s) >=3.9.0 <3.9.6Fix Suggestion:
Update to version 3.9.6org.apache.zookeeper:zookeeper (JAVA):
Affected version(s) >=3.8.0 <3.8.7Fix Suggestion:
Update to version 3.8.7Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Missing Authorization
EPSS
Base Score:
0.57