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CVE-2026-59739

Apache ZooKeeper: Information disclosure via SetWatches reconnect replay

cve-program · severity unknownCVSS unknownCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-59739

Published

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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-59739

Published

org.apache.zookeeper:zookeeper

https://repo.maven.apache.org/maven2

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "Apache Software Foundation",
                    "product": "Apache ZooKeeper",
                    "collectionURL": "https://repo.maven.apache.org/maven2",
                    "packageName": "org.apache.zookeeper:zookeeper",
                    "packageURL": "pkg:maven/org.apache.zookeeper/zookeeper",
                    "versions": [
                        {
                            "status": "affected",
                            "version": "3.9.0",
                            "lessThanOrEqual": "3.9.5",
                            "versionType": "maven"
                        },
                        {
                            "status": "affected",
                            "version": "3.8.0",
                            "lessThanOrEqual": "3.8.6",
                            "versionType": "semver"
                        }
                    ],
                    "defaultStatus": "unaffected"
                }

Original source record · Cite this exact observation · Complete original publisher JSON