CVE-2026-33557 (GCVE-0-2026-33557)
Vulnerability from cvelistv5
Published
2026-04-20 13:28
Modified
2026-04-20 14:30
Severity ?
CWE
  • CWE-1285 - Improper Validation of Specified Index, Position, or Offset in Input
Summary
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.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.
Impacted products
Vendor Product Version
Apache Software Foundation Apache Kafka Version: 4.1.0    4.1.1
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Show details on NVD website


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  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
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