`CVE-2026-59739` Apache ZooKeeper

Affected software	Apache ZooKeeper
Severity	7.5 High CVSS 3.1
Weakness	Missing authorization (CWE-862)
Published	16 Sep 2026
Updated	18 Sep 2026

Published 59 days ago. NVD often adds the list of affected products days or weeks after a CVE is published, and the other sources we check lag too. The scope and status here may change.

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.

Exploitation status

No public exploit

No exploit has been reported in the sources we check.

CISA KEV not listed
VulnCheck KEV not listed
CISA Vulnrichment exploitation: none
Indexed PoC none indexed
EPSS 0.55% chance in 30 days

Waratek protection

No exploit published

Within Waratek scope. In the sources we check, nobody has published exploit code for this CVE or reported it being exploited.

VRT has not found a public code change for this CVE yet.

Protection none
Action not pursued
Review automated Upstream data
Record active

Decided by	Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read
Finding	This CVE affects a known product, but nothing published names a fix and nothing published shows an exploit. That is a statement about the evidence, not about the defect — it does not mean the vulnerability is unimportant or unreachable, only that neither of the two things VRT can act on exists.

Decided by

Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read

Finding

This CVE affects a known product, but nothing published names a fix and nothing published shows an exploit. That is a statement about the evidence, not about the defect — it does not mean the vulnerability is unimportant or unreachable, only that neither of the two things VRT can act on exists.

Affected software and releases

Oracle advisories

Advisory	Type	Quarter	Products Oracle names in its risk matrix
Oracle Critical Patch Update October 2026 ↗	CPU	2026-Q4	Oracle Construction and Engineering / Platform (Apache ZooKeeper) (21.12.0-21.12.17, 22.12.0-22.12.15, 23.12.0-23.12.16, 24.12.0-24.12.16, 25.12.0-25.12.9)

Advisory

Type

Quarter

Products Oracle names in its risk matrix

Oracle Critical Patch Update October 2026 ↗

CPU

2026-Q4

Oracle Construction and Engineering / Platform (Apache ZooKeeper) (21.12.0-21.12.17, 22.12.0-22.12.15, 23.12.0-23.12.16, 24.12.0-24.12.16, 25.12.0-25.12.9)

Oracle components and versions

Family	Component	Versions, as Oracle lists them	Read as
Oracle Construction and Engineering	Platform (Apache ZooKeeper)	21.12.0-21.12.17, 22.12.0-22.12.15, 23.12.0-23.12.16, 24.12.0-24.12.16, 25.12.0-25.12.9

Family

Component

Versions, as Oracle lists them

Read as

Oracle Construction and Engineering

Platform (Apache ZooKeeper)

21.12.0-21.12.17, 22.12.0-22.12.15, 23.12.0-23.12.16, 24.12.0-24.12.16, 25.12.0-25.12.9

Products and versions

1 product, 2 version entries

Source	Vendor	Product	Scheme	Affected versions
nvd	apache	zookeeper	generic	≥ 3.8.0 and ＜ 3.8.7 · ≥ 3.9.0 and ＜ 3.9.6

Source

Vendor

Product

Scheme

Affected versions

nvd

apache

zookeeper

generic

≥ 3.8.0 and ＜ 3.8.7 · ≥ 3.9.0 and ＜ 3.9.6

References

URL	Tags
https://lists.apache.org/thread/v0lrwsbdxvx6w67p3z7fxf3hzyncq55l	Mailing List, Vendor Advisory

URL

Timeline

Published	2026-09-16	By the CVE Program.
NVD record modified	2026-09-18	NVD's own last-modified date for this record.

Published

2026-09-16

By the CVE Program.

NVD record modified

2026-09-18

NVD's own last-modified date for this record.

How VRT decided (18 of 24 rules ran)

18 of 24 rules ran. The rest didn't run because an earlier rule had already settled the CVE.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? the first rule that matches decides

1 rejected no match CVE Program withdrawal of this identifier

scope: Is it a vulnerability Waratek protects? the first rule that matches decides

2 armr-patch-file no match An ARMR patch file on disk for this CVE

3 armr-secure-rule-file no match An ARMR security-rule template on disk for this CVE

4 manual-classification no match A researcher's recorded decision for this specific CVE

5 manual classification no match Manual classification of this CVE in the legacy dataset

6 non-java-upstream no match A root cause in non-Java code: an OS kernel, a C library, or a bundled runtime

7 oracle-component no match The defect being in a component of a tracked product the agent does not reach: JavaFX, the Java SE installer, the JInitiator browser plug-in, the native WebLogic proxy plug-in, or a native part of Oracle Application Server or Collaboration Suite (HTTP Server, Web Cache, Internet Directory, mail and calendar servers). Oracle gives these no CPE of their own and names them only in the description.

8 java-client-side no match Oracle's own risk-matrix note saying the CVE is reached only through untrusted code in the Java sandbox (applets, Web Start) or only through a client installation of Java, so a server running its own trusted code is not exposed

9 osv-maven no match An OSV.dev record of this CVE affecting a package published to Maven Central. When every such package is one business applications do not use (Minecraft mods and launchers, Fastjson) and no tracked product is named by CPE, it settles the CVE as Outside Waratek scope instead

10 cna-maven-package matched In scope CNA declares the affected component is a Maven artifact

11 known-cpe-product not reached An NVD CPE naming a product ARMR tracks

12 cna-cpe-product not reached A CPE the CNA published naming a tracked product. Oracle publishes these on advisory day, months before NVD.

13 oracle-advisory-family not reached A tracked product family named in Oracle's own risk matrix. CPE cannot carry a suite name, only a module.

14 cna-named-product not reached A tracked product named in words by the CVE's own CNA, on a record with no CPE yet. Apache and Eclipse publish these on advisory day, before NVD adds CPE data.

15 non-deployable-product not reached The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached

16 unmatched-product not reached No tracked product matched above, and none present at all

disposition: What do we do about one that is? every rule runs

17 patch-hint no match A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug

18 open-source-maven no match The affected package being open source on Maven, so the fix can be read

19 poc-derivable no match An indexed exploit clearing the evidence bar to reverse-engineer, where there is no source to read

20 no-exploit decided it matched No exploit published No public exploits or POCs found in Exploit-DB, Nuclei templates, Metasploit modules, or GitHub POC repositories, and CISA's Vulnrichment assessment records no demonstrated exploit. No upstream fix reference or open-source Maven package was found either, so there is nothing to act on from either direction.

21 secure-rule-match no match A vulnerability class already blocked by an ARMR security rule

22 exploited-no-fix-or-poc skipped Somebody exploiting this CVE (a CISA or VulnCheck KEV listing, or a CISA verdict of active exploitation), with no fix, source code or PoC to build a rule from

23 below-action-threshold skipped Medium or Low severity, no CISA or VulnCheck KEV listing, no PoC clearing the evidence bar, no CISA verdict, no Oracle advisory

24 no-exploit-published skipped Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all

Products the scope rules checked

The products this CVE's record names, and whether VRT tracks each one. The scope rules decided on these.

Vendor Product Tracked CPE Source

apache zookeeper tracked cpe:2.3:a:apache:zookeeper:*:*:*:*:*:*:*:* yaml

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