GHSA-28jg-cgg7-j4wc
Apache Kafka does not validate JWT tokens in its OAUTHBEARER authentication implementation
Quick fix
GHSA-28jg-cgg7-j4wc — org.apache.kafka:kafka-clients: upgrade to the fixed version with the command below.
# pom.xml: bump <version>4.1.2</version> for org.apache.kafka:kafka-clientsDetails
A security vulnerability has been identified in Apache Kafka. By default, the broker property `sasl.oauthbearer.jwt.validator.class` is set to `org.apache.kafka.common.security.oauthbearer.DefaultJwtValidator`. It accepts any JWT token without validating its signature, issuer, or audience. An attacker can generate a JWT token from any issuer with the `preferred_username` set to any user, and the broker will accept it.
Apache advises Kafka users using kafka v4.1.0 or v4.1.1 to set the config `sasl.oauthbearer.jwt.validator.class` to `org.apache.kafka.common.security.oauthbearer.BrokerJwtValidator` explicitly to avoid this vulnerability. Since Kafka v4.1.2 and v4.2.0 and later, the issue is fixed and will correctly validate the JWT token.
Are you affected?
Enter the version of the package you're using.
Affected packages
4.1.0Fixed in: 4.1.2# pom.xml: bump <version>4.1.2</version> for org.apache.kafka:kafka-clientsReferences
- https://nvd.nist.gov/vuln/detail/CVE-2026-33557[ADVISORY]
- https://github.com/apache/kafka/commit/01d8e7db8d08dbd538892b409457ea6bfcc2a422[WEB]
- https://github.com/apache/kafka[PACKAGE]
- https://kafka.apache.org/cve-list[WEB]
- https://lists.apache.org/thread/v57o00hm6yszdpdnvqx2ss4561yh953h[WEB]
- http://www.openwall.com/lists/oss-security/2026/04/17/2[WEB]