Apache Kafka does not validate JWT tokens in its OAUTHBEARER authentication implementation

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 attacke...

CVE-2026-33557

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. A...

Apache Kafka Message Dispatcher Client SSRF

The vulnerabilities of the sasl.oauthbearer.token.endpoint.url and sasl.oauthbearer.jwks.endpoint.url configurations in the Apache Kafka message dispatcher client are related to insufficient validation of incoming requests. Exploiting these vulnerabilities could allow a malicious actor to perform...

CVE-2025-27817

A flaw was found in apache-kafka. The Kafka client improperly handles configuration data for SASL/OAUTHBEARER connections, allowing an attacker to specify a crafted token endpoint URL. This allows for arbitrary file reads and server-side request forgery SSRF by a malicious client. Consequently,...

Apache Kafka Client Arbitrary File Read and Server Side Request Forgery Vulnerability

A possible arbitrary file read and SSRF vulnerability has been identified in Apache Kafka Client. Apache Kafka Clients accept configuration data for setting the SASL/OAUTHBEARER connection with the brokers, including "sasl.oauthbearer.token.endpoint.url" and "sasl.oauthbearer.jwks.endpoint.url"...

CVE-2025-27817 Apache Kafka Client: Arbitrary file read and SSRF vulnerability

A possible arbitrary file read and SSRF vulnerability has been identified in Apache Kafka Client. Apache Kafka Clients accept configuration data for setting the SASL/OAUTHBEARER connection with the brokers, including "sasl.oauthbearer.token.endpoint.url" and "sasl.oauthbearer.jwks.endpoint.url"...