Review reviewCritical

CVE-2026-33557

Apache Software Foundation Apache Kafka, OpenShift Serverless, Red Hat build of Apache Camel 4 for Quarkus 3

A possible 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. We advise the 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.Broke...

CVSS: 9.1
EPSS: 0.68%
CISA KEV: Not listed
Published: 2026.04.20

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.68%

Technical severityCVSS 9.1

Vulnerability overview

Affected product and versions

Product: Apache Software Foundation Apache Kafka, OpenShift Serverless, Red Hat build of Apache Camel 4 for Quarkus 3
Affected versions: >= 4.1.0 <= 4.1.1, >= 4.1.0 < 4.1.2
Fixed versions: 4.1.2

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Apache Software Foundation Apache Kafka, OpenShift Serverless, Red Hat build of Apache Camel 4 for Quarkus 3 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE: CWE-1285, CWE-303