CVE-2026-33557
EUVD-2026-2384620.04.2026, 14:16
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.Enginsight
Affected Products (NVD)
| Vendor | Product | Version |
|---|---|---|
| apache | kafka | 4.1.0 ≤ 𝑥 < 4.1.2 |
𝑥
= Vulnerable software versions
Common Weakness Enumeration
- CWE-1285 - Improper Validation of Specified Index, Position, or Offset in InputThe product receives input that is expected to specify an index, position, or offset into an indexable resource such as a buffer or file, but it does not validate or incorrectly validates that the specified index/position/offset has the required properties.
- CWE-303 - Incorrect Implementation of Authentication AlgorithmThe requirements for the software dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect.
References