CVE-2026-59739
Information disclosure via SetWatches reconnect replay in Apache ZooKeeper due to missing ACL check.
Technology
Apache ZooKeeper
CVSS Score
7.5 / 10.0
Affected Versions
>=3.8.0 <3.8.7; >=3.9.0 <3.9.6
Upstream Fix
See upstream advisory
Published
September 16, 2026
OSSeva Coverage
Fixed upstream
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 d
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