Apache Kafka
Monthly
Improper authorization in Apache Kafka 4.0.0-4.3.0 arises from a discrepancy between the documented ACL requirement and the actual runtime behavior of the CONSUMER_GROUP_DESCRIBE (API key 69) endpoint. The API checks for DESCRIBE permission on the GROUP resource at runtime, while official Kafka documentation and KIP-848 specify READ as the required operation - causing administrators who followed the documentation to configure ACLs that either over-grant READ access to users who should only observe group metadata, or under-restrict DESCRIBE-only users who can nonetheless access sensitive consumer group state. No public exploit has been identified at time of analysis, and EPSS exploitation probability is 0.02% (4th percentile), indicating negligible opportunistic exploitation risk.
Apache Kafka 4.1.0 and 4.1.1 accept forged JWT tokens without signature validation, allowing remote unauthenticated attackers to authenticate as any user and gain unauthorized access to Kafka resources. The default SASL/OAUTHBEARER validator (DefaultJwtValidator) fails to verify token signatures, issuers, or audiences, enabling complete authentication bypass. CVSS 9.1 (Critical) with network vector and no privileges required. SSVC indicates the vulnerability is automatable with partial technical impact. No active exploitation confirmed at time of analysis, but the attack requires minimal sophistication and could be scripted trivially given the token acceptance behavior.
Improper authorization in Apache Kafka 4.0.0-4.3.0 arises from a discrepancy between the documented ACL requirement and the actual runtime behavior of the CONSUMER_GROUP_DESCRIBE (API key 69) endpoint. The API checks for DESCRIBE permission on the GROUP resource at runtime, while official Kafka documentation and KIP-848 specify READ as the required operation - causing administrators who followed the documentation to configure ACLs that either over-grant READ access to users who should only observe group metadata, or under-restrict DESCRIBE-only users who can nonetheless access sensitive consumer group state. No public exploit has been identified at time of analysis, and EPSS exploitation probability is 0.02% (4th percentile), indicating negligible opportunistic exploitation risk.
Apache Kafka 4.1.0 and 4.1.1 accept forged JWT tokens without signature validation, allowing remote unauthenticated attackers to authenticate as any user and gain unauthorized access to Kafka resources. The default SASL/OAUTHBEARER validator (DefaultJwtValidator) fails to verify token signatures, issuers, or audiences, enabling complete authentication bypass. CVSS 9.1 (Critical) with network vector and no privileges required. SSVC indicates the vulnerability is automatable with partial technical impact. No active exploitation confirmed at time of analysis, but the attack requires minimal sophistication and could be scripted trivially given the token acceptance behavior.