CVE-2024-23944: Apache ZooKeeper: Information disclosure in persistent watcher handling

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-03-15 · updated 2026-06-17
Weakness: CWE-862

Description

Information disclosure in persistent watchers handling in Apache ZooKeeper due to missing ACL check. It allows an attacker to monitor child znodes by attaching a persistent watcher (addWatch command) to a parent which the attacker has already access to. ZooKeeper server doesn't do ACL check when the persistent watcher is triggered and as a consequence, the full path of znodes that a watch event gets triggered upon is exposed to the owner of the watcher. 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 3.9.2, 3.8.4 which fixes the issue.

Affected products

Apache Software Foundation Apache ZooKeeper: from 3.6.0 through 3.7.2; from 3.8.0 before 3.8.4; from 3.9.0 before 3.9.2 — fixed in 3.8.4, 3.9.2

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache ZooKeeper 3.8.4, 3.9.2. Check the vendor advisory for mitigations.

References

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