CVE-2026-59739
No exploitation reported by the sources we read.
- Published2026-09-16
- Fixed in3.9.6 · 3.8.7
- WeaknessCWE-862
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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.
Timeline
dates in UTC- 2026-09-1610:16CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-59739?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-59739?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD · OSV| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 3.9 | ≥ 3.9.0, < 3.9.6 | 3.9.6 | NVD · OSV |
| 3.8 | ≥ 3.8.0, < 3.8.7 | 3.8.7 | NVD · OSV |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
zookeeper: Apache ZooKeeper: Information disclosure via SetWatches reconnect replay
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 · +33 more
Fix
- Update Apache zookeeper to 3.9.6 · 3.8.7
- Workaround from the vendor Red Hat Product Security CVE-2026-59739 · 36 productsUpdate to Apache ZooKeeper 3.8.7, 3.9.6, or later.
- No fix available, says the vendor Red Hat Product Security CVE-2026-59739 · 36 productsFix deferred
Advisories and patches
- lists.apache.orgVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Published
- 2026-09-16
- Last Modified
- 2026-09-18
- NVD status
- Analyzed
Frequently asked questions
What is CVE-2026-59739?
Is CVE-2026-59739 actively exploited?
What is the CVSS score for CVE-2026-59739?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.