Vulnerabilities in pkg:maven/org.apache.zookeeper/zookeeper

PACKAGE
Advisory Identifier: GHSA-7xrh-hqfc-g7qr
Advisory Summary

CVE-2026-24281 is a HIGH (CVSS 7.4) reverse-dns fallback enables hostname verification vulnerability (CWE-295: Improper Certificate Validation) affecting Apache ZooKeeper libraries in the Maven ecosystem. The issue involves reverse-dns fallback enables hostname verification bypass in zookeeper zktrustmanager. Remediation is available by upgrading affected packages to version 3.8.6, 3.9.5.

9 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:maven/org.apache.zookeeper/zookeeper

9 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:maven/org.apache.zookeeper/zookeeper. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-7xrh-hqfc-g7qr CVE-2026-24281 HIGH Apache ZooKeeper: Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager
GHSA-crhr-qqj8-rpxc CVE-2026-24308 HIGH Apache ZooKeeper has improper handling of configuration values
GHSA-2hmj-97jw-28jh CVE-2025-58457 MODERATE Apache ZooKeeper: Insufficient Permission Check in AdminServer Snapshot/Restore Commands
GHSA-r978-9m6m-6gm6 CVE-2024-23944 MODERATE Apache ZooKeeper vulnerable to information disclosure in persistent watchers handling
GHSA-g93m-8x6h-g5gv CVE-2024-51504 HIGH Apache ZooKeeper: Authentication bypass with IP-based authentication in Admin Server
GHSA-7286-pgfv-vxvh CVE-2023-44981 CRITICAL Authorization Bypass Through User-Controlled Key vulnerability in Apache ZooKeeper
GHSA-7cwj-j333-x7f7 CVE-2017-5637 HIGH Uncontrolled Resource Consumption in Apache ZooKeeper
GHSA-ccqf-c5hq-77mp CVE-2018-8012 HIGH Missing Authorization in Apache ZooKeeper
GHSA-2hw2-62cp-p9p7 CVE-2019-0201 MODERATE Access control bypass in Apache ZooKeeper

CVE-2026-24281 at a Glance

CVE Identifier CVE-2026-24281
GHSA Identifier GHSA-7xrh-hqfc-g7qr
Severity HIGH
CVSS v3.1 Base Score 7.4
CWE Classification CWE-295: Improper Certificate Validation
Affected Product Apache ZooKeeper
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-24281

To remediate this vulnerability, upgrade all affected Apache ZooKeeper dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.apache.zookeeper:zookeeper fixed: 3.8.6
<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.8.6</version>
</dependency>
org.apache.zookeeper:zookeeper fixed: 3.9.5
<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.9.5</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

mvn dependency:tree -Dincludes=org.apache.zookeeper

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-24281, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.apache.zookeeper

Analyze the terminal output to locate any version of Apache ZooKeeper in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.8.6), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.zookeeper command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-295: Improper Certificate Validation, where the product does not validate, or incorrectly validates, a certificate. In Apache ZooKeeper, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Hostname verification in Apache ZooKeeper ZKTrustManager falls back to reverse DNS (PTR) when IP SAN validation fails, allowing attackers who control or spoof PTR records to impersonate ZooKeeper servers or clients with a valid certificate for the PTR name. It's important to note that attacker must present a certificate which is trusted by ZKTrustManager which makes the attack vector harder to exploit. Users are recommended to upgrade to version 3.8.6 or 3.9.5, which fixes this issue by introducing a new configuration option to disable reverse DNS lookup in client and quorum protocols.

CVE-2026-24281 Affected Apache ZooKeeper Versions

2 component(s)
Fixed Versions:
3.8.63.9.5
Product / Package Ecosystem Affected Versions Fixed Version
org.apache.zookeeper:zookeeper
Maven
≥ 3.8.0
< 3.8.6
3.8.6
org.apache.zookeeper:zookeeper
Maven
≥ 3.9.0
< 3.9.5
3.9.5

References

Frequently Asked Questions

What is CVE-2026-24281?
CVE-2026-24281 is a security vulnerability in Apache ZooKeeper involving Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager under CWE-295: Improper Certificate Validation.
Which Apache ZooKeeper versions are affected?
Affected versions include releases prior to 3.8.6, 3.9.5 across affected packages: org.apache.zookeeper:zookeeper.
What version fixes CVE-2026-24281?
Upgrading to 3.8.6, 3.9.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is zookeeper affected?
Yes, org.apache.zookeeper:zookeeper is affected in releases prior to 3.8.6, 3.9.5. Upgrade your dependency to 3.8.6, 3.9.5 or later.
What is the CVSS score of CVE-2026-24281?
CVE-2026-24281 has a CVSS v3.1 base score of 7.4 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-24281?
CVE-2026-24281 is classified under CWE-295: Improper Certificate Validation (The product does not validate, or incorrectly validates, a certificate.).
How can I check Maven dependencies for CVE-2026-24281?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.zookeeper'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7xrh-hqfc-g7qr",
  "modified" : "2026-03-10T19:32:52Z",
  "published" : "2026-03-07T09:30:15Z",
  "aliases" : [ "CVE-2026-24281" ],
  "summary" : "Apache ZooKeeper: Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager",
  "details" : "Hostname verification in Apache ZooKeeper ZKTrustManager falls back to reverse DNS (PTR) when IP SAN validation fails, allowing attackers who control or spoof PTR records to impersonate ZooKeeper servers or clients with a valid certificate for the PTR name. It's important to note that attacker must present a certificate which is trusted by ZKTrustManager which makes the attack vector harder to exploit. Users are recommended to upgrade to version 3.8.6 or 3.9.5, which fixes this issue by introducing a new configuration option to disable reverse DNS lookup in client and quorum protocols.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.zookeeper:zookeeper"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.8.0"
      }, {
        "fixed" : "3.8.6"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.zookeeper:zookeeper"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.9.0"
      }, {
        "fixed" : "3.9.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24281"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/zookeeper/commit/66c4efecdda1302d9cfb3af9eedb122b74452bf3"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/apache/zookeeper"
  }, {
    "type" : "WEB",
    "url" : "https://issues.apache.org/jira/browse/ZOOKEEPER-4986"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/03/07/4"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-295", "CWE-297" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-10T19:32:52Z",
    "nvd_published_at" : "2026-03-07T09:16:07Z"
  }
}