CVE-2026-59739

Apache ZooKeeper: Information disclosure via SetWatches reconnect replay

HIGH
7.5
CVSS Score
Published: September 16, 2026 at 09:26 AM UTC
Updated: September 18, 2026 at 02:49 PM UTC
1 product affected across 1 vendorZookeeper

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

3.8.0 ≤ v ≤ 3.8.63.8.0 ≤ v < 3.8.73.9.0 ≤ v ≤ 3.9.53.9.0 ≤ v < 3.9.63.8.03.9.0
Affected range stops below 3.8.7, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.9.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

Vendor AdvisoryMailing List
Source: cverecord
https://lists.apache.org/thread/v0lrwsbdxvx6w67p3z7fxf3hzyncq55l

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-862

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