Vulnerability 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 Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Apache | Zookeeper | >= 3.8.0, < 3.8.7 |
Related Weaknesses (CWE)
References
- https://lists.apache.org/thread/v0lrwsbdxvx6w67p3z7fxf3hzyncq55lMailing ListVendor Advisory
FAQ
What is CVE-2026-59739?
CVE-2026-59739 is a vulnerability with a CVSS score of 7.5 (HIGH). 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, ...
How severe is CVE-2026-59739?
CVE-2026-59739 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-59739?
Check the references section above for vendor advisories and patch information. Affected products include: Apache Zookeeper.