Vulnerability record · CVE-2026-59739 · published 16 September 2026

CVE-2026-59739: Apache zookeeper missing authorization vulnerability

Apache · Zookeeper

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.

7.5 CVSS 3.1 High EPSS 0.55% · top 56.1% CWE-862 · Missing authorization

7.5CVSS 3.1 base score

0.55%EPSS exploitation probability, 30 days

NoNot in CISA KEV

1Affected product versions listed by NVD

1References

18 Sep 2026Last modified by NVD

Description

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

Zookeeper Apache

References

Link	Tags
https://lists.apache.org/thread/v0lrwsbdxvx6w67p3z7fxf3hzyncq55l	Mailing ListVendor Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-59739), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.