Evidence used
- No CISA KEV confirmation is currently recorded.
- The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
- EPSS is 0.55% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-59739High confidence
Apache ZooKeeper: Information disclosure via SetWatches reconnect replay
Apache Software Foundation · Apache ZooKeeper
7.5HighCVSS 3.1
Patch only the product branches with a verified fix
Fix availability varies by productHigh technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 38 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Apply the linked authoritative mitigation while planning the permanent fix.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Apache Software Foundation Apache ZooKeeper and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 38 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Red Hat Product Security: 36 affected or under-investigation product states without a fixed product state in the same current advisory
- Debian Security Tracker: 2 affected package states with no published fix
Distribution package intelligence
5 package statesRelease-specific package status
Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Package result overrides the generic status
BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 2 affected package states shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | zookeeper | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian bookwormbookworm · source | zookeeper | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian forkyforky · source | zookeeper | Vendor fix publishedDebian records a fixed source-package version for this release. | 3.9.6-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian sidsid · source | zookeeper | Vendor fix publishedDebian records a fixed source-package version for this release. | 3.9.6-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | zookeeper | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 6 Oct 2026 |
Direct vendor intelligence
1 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
CVE-2026-59739 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityzookeeper: Apache ZooKeeper: Information disclosure via SetWatches reconnect replay
The vendor explicitly identifies these products as affected by this CVE.
- parent as a component of Red Hat AMQ Broker 7
- zookeeper as a component of Red Hat AMQ Broker 7
- zookeeper-jute as a component of Red Hat AMQ Broker 7
- flink-shaded-zookeeper-3 as a component of Red Hat build of Apache Camel 4 for Quarkus 3
- flink-shaded-zookeeper-3 as a component of Red Hat build of Apache Camel for Spring Boot 4
- flink-shaded-zookeeper-parent as a component of Red Hat build of Apache Camel for Spring Boot 4
- camel-spring-cloud-zookeeper as a component of Red Hat Fuse 7
- camel-spring-cloud-zookeeper-starter as a component of Red Hat Fuse 7
- camel-zookeeper as a component of Red Hat Fuse 7
- camel-zookeeper-master as a component of Red Hat Fuse 7
- camel-zookeeper-master-starter as a component of Red Hat Fuse 7
- camel-zookeeper-starter as a component of Red Hat Fuse 7
- Summary
- A flaw was found in Apache ZooKeeper. This vulnerability allows a remote attacker to discover paths that should be restricted by Access Control Lists (ACLs). By registering watches on non-existent paths and then reconnecting after these paths are created with restricted ACLs, the attacker can bypass security checks. This information disclosure could expose sensitive path details, such as usernames or login identifiers.
- Remediation
- Update to Apache ZooKeeper 3.8.7, 3.9.6, or later.
High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 38 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
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.
What
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.
Why
The application reaches a protected operation without first confirming that the requester is authorised.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may obtain information outside the intended access boundary.
What
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.
Why
The application reaches a protected operation without first confirming that the requester is authorised.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may obtain information outside the intended access boundary.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → Missing Authorization → obtain information outside the intended access boundary
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-862 ↗
CWE-862: Missing Authorization. The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix availability varies by product
- Affected
- parent as a component of Red Hat AMQ Broker 7
- zookeeper as a component of Red Hat AMQ Broker 7
- zookeeper-jute as a component of Red Hat AMQ Broker 7
- flink-shaded-zookeeper-3 as a component of Red Hat build of Apache Camel 4 for Quarkus 3
- flink-shaded-zookeeper-3 as a component of Red Hat build of Apache Camel for Spring Boot 4
- flink-shaded-zookeeper-parent as a component of Red Hat build of Apache Camel for Spring Boot 4
- camel-spring-cloud-zookeeper as a component of Red Hat Fuse 7
- camel-spring-cloud-zookeeper-starter as a component of Red Hat Fuse 7
- camel-zookeeper as a component of Red Hat Fuse 7
- camel-zookeeper-master as a component of Red Hat Fuse 7
- camel-zookeeper-master-starter as a component of Red Hat Fuse 7
- camel-zookeeper-starter as a component of Red Hat Fuse 7
- flink-shaded-zookeeper-3 as a component of Red Hat Fuse 7
- org.linkedin.zookeeper-impl as a component of Red Hat Fuse 7
- spring-cloud-starter-zookeeper as a component of Red Hat Fuse 7
- spring-cloud-starter-zookeeper-discovery as a component of Red Hat Fuse 7
- spring-cloud-zookeeper-core as a component of Red Hat Fuse 7
- spring-cloud-zookeeper-discovery as a component of Red Hat Fuse 7
- zookeeper as a component of Red Hat Fuse 7
- zookeeper-jute as a component of Red Hat Fuse 7
- parent as a component of Red Hat JBoss Enterprise Application Platform 8
- zookeeper as a component of Red Hat JBoss Enterprise Application Platform 8
- parent as a component of Red Hat JBoss Enterprise Application Platform Expansion Pack
- zookeeper as a component of Red Hat JBoss Enterprise Application Platform Expansion Pack
- offline-knowledge-portal/rhokp-rhel9 as a component of Red Hat Offline Knowledge Portal
- rhoai/odh-modelmesh-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
- rhoai/odh-spark-operator-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
- rhoai/odh-th-torch-cpu-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
- rhoai/odh-th-torch-cuda-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
- rhoai/odh-th06-cpu-torch210-py312-rhel9 as a component of Red Hat OpenShift AI (RHOAI)
- and 6 more
- Action
- Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
- Workaround
- Update to Apache ZooKeeper 3.8.7, 3.9.6, or later.
04
Evidence and provenance
Published 16 Sept 2026 · Last source change 17 Sept 2026, 19:19 UTC · CWE-862 · Missing Authorization
CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source FIRST · tracked since 2026-09-16
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-80330
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: lists.apache.org/v0lrwsbdxvx6w67p3z7fxf3hzyncq55l.security@apache.org ↗
- Before
- no authoritative guidance recorded
- After
- vendor advisory: lists.apache.org/v0lrwsbdxvx6w67p3z7fxf3hzyncq55l
- SeveritySeverity changed from Unknown to High.CISA ADP ↗
- Before
- Unknown
- After
- High
- CVSS scoreCVSS score changed from not recorded to 7.5 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).CISA ADP ↗
- Before
- not recorded
- After
- 7.5 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
- ENISA EUVD mappingEUVD-2026-80330 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-80330"}
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.