High
zookeeper — security advisory
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.
- Products
- zookeeper
- Affected versions
- 3.4.10-2, 3.4.10-3, 3.4.13-1, 3.4.13-3, 3.4.13-3build1, 3.4.13-3ubuntu0.1~esm1, 3.4.13-4, 3.4.13-5, 3.4.13-5build1, 3.4.13-5ubuntu0.1, 3.4.13-5ubuntu4, 3.4.13-6ubuntu2, 3.4.13-6ubuntu3, 3.4.13-6ubuntu4, 3.4.13-6ubuntu4.1, 3.4.5+dfsg-1, 3.4.5+dfsg-1ubuntu0.1~esm1, 3.4.5+dfsg-1ubuntu0.1~esm3, 3.4.6-8, 3.4.7-1, 3.4.8-1, 3.4.8-1ubuntu0.1~esm1, 3.4.8-1ubuntu0.1~esm2, 3.8.0-11, 3.9.1-1, 3.9.1-1build1, 3.9.1-1build2, 3.9.3-1build2, 3.9.3-1build3, 3.9.4-1, 3.9.5-1, 3.9.5-2
- Fixed versions
- Not specified
- CVEs
- CVE-2026-59739
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:10 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-59739
zookeeper
Fixed versions: Not specified
zookeeper
Fixed versions: Not specified
zookeeper
Fixed versions: Not specified
zookeeper
Fixed versions: Not specified
zookeeper
Fixed versions: Not specified
zookeeper
Fixed versions: Not specified
zookeeper
Fixed versions: Not specified
zookeeper
Fixed versions: Not specified
Complete source record
{
"id": "63827fb81274c7e1f60c83f3265a750c9c76d5838d3e1ddfb70cb48bad83a21c",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-59739",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-59739",
"summary": "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.",
"evidence": "osv:UBUNTU-CVE-2026-59739",
"products": [
{
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},
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{
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{
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{
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{
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},
{
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{
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{
"name": {
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{
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},
{
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"evidence": "/affected/3/versions"
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{
"value": "3.4.13-4",
"evidence": "/affected/3/versions"
},
{
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},
{
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},
{
"name": {
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},
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{
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"evidence": "/affected/4/versions"
},
{
"value": "3.4.13-6ubuntu2",
"evidence": "/affected/4/versions"
},
{
"value": "3.4.13-6ubuntu3",
"evidence": "/affected/4/versions"
},
{
"value": "3.4.13-6ubuntu4",
"evidence": "/affected/4/versions"
},
{
"value": "3.4.13-6ubuntu4.1",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "zookeeper",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.8.0-11",
"evidence": "/affected/5/versions"
},
{
"value": "3.9.1-1",
"evidence": "/affected/5/versions"
},
{
"value": "3.9.1-1build1",
"evidence": "/affected/5/versions"
},
{
"value": "3.9.1-1build2",
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{
"name": {
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},
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},
{
"value": "3.9.5-2",
"evidence": "/affected/6/versions"
}
]
},
{
"name": {
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},
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"evidence": "/affected/7/versions"
},
{
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"evidence": "/affected/7/versions"
},
{
"value": "3.9.4-1",
"evidence": "/affected/7/versions"
},
{
"value": "3.9.5-1",
"evidence": "/affected/7/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-59739",
"aliases": [
"UBUNTU-CVE-2026-59739"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
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{
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"events": [
{
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}
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}
],
"package": {
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"ecosystem": "Ubuntu:Pro:14.04:LTS"
},
"versions": [
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"3.4.5+dfsg-1ubuntu0.1~esm1",
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},
{
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"binary_version": "3.4.5+dfsg-1ubuntu0.1~esm3"
},
{
"binary_name": "libzookeeper-st2",
"binary_version": "3.4.5+dfsg-1ubuntu0.1~esm3"
},
{
"binary_name": "libzookeeper2",
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{
"binary_name": "python-zookeeper",
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{
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},
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"3.4.7-1",
"3.4.8-1",
"3.4.8-1ubuntu0.1~esm1",
"3.4.8-1ubuntu0.1~esm2"
],
"database_specific": {
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},
"ecosystem_specific": {
"binaries": [
{
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},
{
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"binary_version": "3.4.8-1ubuntu0.1~esm2"
},
{
"binary_name": "libzookeeper-st2",
"binary_version": "3.4.8-1ubuntu0.1~esm2"
},
{
"binary_name": "libzookeeper2",
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},
{
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{
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},
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},
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},
{
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},
{
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{
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},
{
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],
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"purl": "pkg:deb/ubuntu/zookeeper?arch=source&distro=jammy",
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},
"versions": [
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"3.4.13-6ubuntu2",
"3.4.13-6ubuntu3",
"3.4.13-6ubuntu4",
"3.4.13-6ubuntu4.1"
],
"database_specific": {
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},
"ecosystem_specific": {
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},
{
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},
{
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},
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],
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},
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],
"database_specific": {
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},
"ecosystem_specific": {
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},
{
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},
{
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},
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"binary_name": "python3-zookeeper",
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},
{
"binary_name": "zookeeper",
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},
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"ecosystem": "Ubuntu:26.10"
},
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],
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},
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},
{
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{
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},
{
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{
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},
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{
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"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"3.9.3-1build2",
"3.9.3-1build3",
"3.9.4-1",
"3.9.5-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-59739.json"
},
"ecosystem_specific": {
"binaries": [
{
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"binary_version": "3.9.5-1"
},
{
"binary_name": "libzookeeper-mt2",
"binary_version": "3.9.5-1"
},
{
"binary_name": "libzookeeper-st2",
"binary_version": "3.9.5-1"
},
{
"binary_name": "python3-zookeeper",
"binary_version": "3.9.5-1"
},
{
"binary_name": "zookeeper",
"binary_version": "3.9.5-1"
},
{
"binary_name": "zookeeper-bin",
"binary_version": "3.9.5-1"
},
{
"binary_name": "zookeeperd",
"binary_version": "3.9.5-1"
}
]
}
}
],
"modified": "2026-10-17T13:00:28.973987886Z",
"provider": "osv",
"upstream": [
"CVE-2026-59739"
],
"references": [
"https://ubuntu.com/security/CVE-2026-59739",
"https://www.cve.org/CVERecord?id=CVE-2026-59739"
]
},
"related_cves": [
{
"value": "CVE-2026-59739",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 360592,
"published_at": "2026-09-16T10:16:00+00:00"
}