UBUNTU-CVE-2026-84501

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Source
https://ubuntu.com/security/CVE-2026-84501
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84501.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-84501
Upstream
Published
2026-09-16T10:16:00Z
Modified
2026-09-24T02:00:53Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

An unauthenticated attacker can inject arbitrary fake log lines into Apache ZooKeeper's operational log by sending a crafted add_auth("ensemble", ...) request containing newline characters (\n). When the ensemble name doesn't match, EnsembleAuthenticationProvider.handleAuthentication() logs the raw, unsanitized name via LOG.warn(). Because SLF4J's {} placeholder preserves embedded newlines, the attacker can forge complete log entries — with arbitrary timestamps, log levels, class names, and messages — that are visually indistinguishable from genuine ZooKeeper log output. This issue affects Apache ZooKeeper: from 3.9.0 through 3.9.5, from 3.8.0 through 3.8.6. Users are recommended to upgrade to version 3.8.7 or 3.9.6, which fixes the issue.

References

Affected packages

Ubuntu:20.04:LTS
zookeeper

Package

Name
zookeeper
Purl
pkg:deb/ubuntu/zookeeper?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.4.13-1
3.4.13-3
3.4.13-3build1
3.4.13-4
3.4.13-5
3.4.13-5build1
3.4.13-5ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libzookeeper-java",
            "binary_version": "3.4.13-5ubuntu0.1"
        },
        {
            "binary_name": "libzookeeper-mt2",
            "binary_version": "3.4.13-5ubuntu0.1"
        },
        {
            "binary_name": "libzookeeper-st2",
            "binary_version": "3.4.13-5ubuntu0.1"
        },
        {
            "binary_name": "python3-zookeeper",
            "binary_version": "3.4.13-5ubuntu0.1"
        },
        {
            "binary_name": "zookeeper",
            "binary_version": "3.4.13-5ubuntu0.1"
        },
        {
            "binary_name": "zookeeper-bin",
            "binary_version": "3.4.13-5ubuntu0.1"
        },
        {
            "binary_name": "zookeeperd",
            "binary_version": "3.4.13-5ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84501.json"
Ubuntu:22.04:LTS
zookeeper

Package

Name
zookeeper
Purl
pkg:deb/ubuntu/zookeeper?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.4.13-5ubuntu4
3.4.13-6ubuntu2
3.4.13-6ubuntu3
3.4.13-6ubuntu4
3.4.13-6ubuntu4.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libzookeeper-java",
            "binary_version": "3.4.13-6ubuntu4.1"
        },
        {
            "binary_name": "libzookeeper-mt2",
            "binary_version": "3.4.13-6ubuntu4.1"
        },
        {
            "binary_name": "libzookeeper-st2",
            "binary_version": "3.4.13-6ubuntu4.1"
        },
        {
            "binary_name": "python3-zookeeper",
            "binary_version": "3.4.13-6ubuntu4.1"
        },
        {
            "binary_name": "zookeeper",
            "binary_version": "3.4.13-6ubuntu4.1"
        },
        {
            "binary_name": "zookeeper-bin",
            "binary_version": "3.4.13-6ubuntu4.1"
        },
        {
            "binary_name": "zookeeperd",
            "binary_version": "3.4.13-6ubuntu4.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84501.json"
Ubuntu:24.04:LTS
zookeeper

Package

Name
zookeeper
Purl
pkg:deb/ubuntu/zookeeper?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.8.0-11
3.9.1-1
3.9.1-1build1
3.9.1-1build2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libzookeeper-java",
            "binary_version": "3.9.1-1build2"
        },
        {
            "binary_name": "libzookeeper-mt2",
            "binary_version": "3.9.1-1build2"
        },
        {
            "binary_name": "libzookeeper-st2",
            "binary_version": "3.9.1-1build2"
        },
        {
            "binary_name": "python3-zookeeper",
            "binary_version": "3.9.1-1build2"
        },
        {
            "binary_name": "zookeeper",
            "binary_version": "3.9.1-1build2"
        },
        {
            "binary_name": "zookeeper-bin",
            "binary_version": "3.9.1-1build2"
        },
        {
            "binary_name": "zookeeperd",
            "binary_version": "3.9.1-1build2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84501.json"
Ubuntu:26.04:LTS
zookeeper

Package

Name
zookeeper
Purl
pkg:deb/ubuntu/zookeeper?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.9.3-1build2
3.9.3-1build3
3.9.4-1
3.9.5-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libzookeeper-java",
            "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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84501.json"
Ubuntu:Pro:14.04:LTS
zookeeper

Package

Name
zookeeper
Purl
pkg:deb/ubuntu/zookeeper?arch=source&distro=esm-infra-legacy%2Ftrusty

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.4.5+dfsg-1
3.4.5+dfsg-1ubuntu0.1~esm1
3.4.5+dfsg-1ubuntu0.1~esm3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libzookeeper-java",
            "binary_version": "3.4.5+dfsg-1ubuntu0.1~esm3"
        },
        {
            "binary_name": "libzookeeper-mt2",
            "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",
            "binary_version": "3.4.5+dfsg-1ubuntu0.1~esm3"
        },
        {
            "binary_name": "python-zookeeper",
            "binary_version": "3.4.5+dfsg-1ubuntu0.1~esm3"
        },
        {
            "binary_name": "zookeeper",
            "binary_version": "3.4.5+dfsg-1ubuntu0.1~esm3"
        },
        {
            "binary_name": "zookeeper-bin",
            "binary_version": "3.4.5+dfsg-1ubuntu0.1~esm3"
        },
        {
            "binary_name": "zookeeperd",
            "binary_version": "3.4.5+dfsg-1ubuntu0.1~esm3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84501.json"
Ubuntu:Pro:16.04:LTS
zookeeper

Package

Name
zookeeper
Purl
pkg:deb/ubuntu/zookeeper?arch=source&distro=esm-apps%2Fxenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.4.6-8
3.4.7-1
3.4.8-1
3.4.8-1ubuntu0.1~esm1
3.4.8-1ubuntu0.1~esm2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libzookeeper-java",
            "binary_version": "3.4.8-1ubuntu0.1~esm2"
        },
        {
            "binary_name": "libzookeeper-mt2",
            "binary_version": "3.4.8-1ubuntu0.1~esm2"
        },
        {
            "binary_name": "libzookeeper-st2",
            "binary_version": "3.4.8-1ubuntu0.1~esm2"
        },
        {
            "binary_name": "libzookeeper2",
            "binary_version": "3.4.8-1ubuntu0.1~esm2"
        },
        {
            "binary_name": "python-zookeeper",
            "binary_version": "3.4.8-1ubuntu0.1~esm2"
        },
        {
            "binary_name": "zookeeper",
            "binary_version": "3.4.8-1ubuntu0.1~esm2"
        },
        {
            "binary_name": "zookeeper-bin",
            "binary_version": "3.4.8-1ubuntu0.1~esm2"
        },
        {
            "binary_name": "zookeeperd",
            "binary_version": "3.4.8-1ubuntu0.1~esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84501.json"
Ubuntu:Pro:18.04:LTS
zookeeper

Package

Name
zookeeper
Purl
pkg:deb/ubuntu/zookeeper?arch=source&distro=esm-apps%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.4.10-2
3.4.10-3
3.4.13-3
3.4.13-3ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libzookeeper-java",
            "binary_version": "3.4.13-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "libzookeeper-mt2",
            "binary_version": "3.4.13-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "libzookeeper-st2",
            "binary_version": "3.4.13-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "python-zookeeper",
            "binary_version": "3.4.13-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "zookeeper",
            "binary_version": "3.4.13-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "zookeeper-bin",
            "binary_version": "3.4.13-3ubuntu0.1~esm1"
        },
        {
            "binary_name": "zookeeperd",
            "binary_version": "3.4.13-3ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84501.json"