CVE-2026-33558: Kafka clients Apache Kafka Exposes Sensitive Information Vulnerability
MODERATECVE-2026-33558 is a MODERATE (CVSS 5.3) apache kafka exposes sensitive information vulnerability (CWE-532: Insertion of Sensitive Information into Log File) affecting Kafka clients libraries in the Maven ecosystem. The issue involves apache kafka exposes sensitive information in its debug logs. Remediation is available by upgrading affected packages to version 3.9.2, 4.0.1.
CVE-2026-33558 at a Glance
Security Impact
CVSS: 5.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).
How to Fix CVE-2026-33558
To remediate this vulnerability, upgrade all affected Kafka clients dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>3.9.2</version>
</dependency><dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>4.0.1</version>
</dependency>Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:tree -Dincludes=org.apache.kafkaHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-33558, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=org.apache.kafkaAnalyze the terminal output to locate any version of Kafka clients in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.9.2), your application is affected.
Note: The mvn dependency:tree -Dincludes=org.apache.kafka 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-532: Insertion of Sensitive Information into Log File, where the product writes sensitive information to a log file. In Kafka clients, 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
CVE-2026-33558 Affected Kafka clients Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
org.apache.kafka:kafka-clients
|
Maven |
≥ 0.11.0
< 3.9.2
|
3.9.2
|
|
org.apache.kafka:kafka-clients
|
Maven |
≥ 4.0.0
< 4.0.1
All 1 versions
4.0.0
|
4.0.1
|
References
Frequently Asked Questions
What is CVE-2026-33558?
Which Kafka clients versions are affected?
What version fixes CVE-2026-33558?
Is kafka-clients affected?
What is the CVSS score of CVE-2026-33558?
What CWE is associated with CVE-2026-33558?
How can I check Maven dependencies for CVE-2026-33558?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-wf66-mphr-4c4r",
"modified" : "2026-04-24T20:37:18Z",
"published" : "2026-04-20T15:31:52Z",
"aliases" : [ "CVE-2026-33558" ],
"summary" : "Apache Kafka exposes sensitive information in its DEBUG logs",
"details" : "Information exposure vulnerability has been identified in Apache Kafka.\n\nThe NetworkClient component will output entire requests and responses information in the DEBUG log level in the logs. By default, the log level is set to INFO level. If the DEBUG level is enabled, the sensitive information will be exposed via the requests and responses output log. The entire lists of impacted requests and responses are:\n\n\n * AlterConfigsRequest\n\n * AlterUserScramCredentialsRequest\n\n * ExpireDelegationTokenRequest\n\n * IncrementalAlterConfigsRequest\n\n * RenewDelegationTokenRequest\n\n * SaslAuthenticateRequest\n\n * createDelegationTokenResponse\n\n * describeDelegationTokenResponse\n\n * SaslAuthenticateResponse\n\n\nThis issue affects Apache Kafka: from any version supported the listed API above through v3.9.1, v4.0.0. Apache advises Kafka users to upgrade to v3.9.2, v4.0.1, or later to avoid this vulnerability.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "org.apache.kafka:kafka-clients"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0.11.0"
}, {
"fixed" : "3.9.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "org.apache.kafka:kafka-clients"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.0.0"
}, {
"fixed" : "4.0.1"
} ]
} ],
"versions" : [ "4.0.0" ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33558"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/apache/kafka"
}, {
"type" : "WEB",
"url" : "https://kafka.apache.org/cve-list"
}, {
"type" : "WEB",
"url" : "https://lists.apache.org/thread/pz5g4ky3h0k91tfd14p0dzqjp80960kl"
}, {
"type" : "WEB",
"url" : "http://www.openwall.com/lists/oss-security/2026/04/17/3"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-532" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-04-24T20:37:18Z",
"nvd_published_at" : "2026-04-20T14:16:19Z"
}
}