CVE-2025-27817

Name of the Vulnerable Software and Affected Versions Apache Kafka versions 3.1.0 through 3.9.0 Apache Kafka version 3.9.1 and later require explicit configuration of allowed URLs

Description 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. Apache Kafka allows clients to read an arbitrary file and return the content in the error log, or sending requests to an unintended location. In applications where Apache Kafka Clients configurations can be specified by an untrusted party, attackers may use the sasl.oauthbearer.token.endpoint.url and sasl.oauthbearer.jwks.endpoint.url configuration to read arbitrary contents of the disk and environment variables or make requests to an unintended location. This flaw may be used in Apache Kafka Connect to escalate from REST API access to filesystem/environment/URL access, which may be undesirable in certain environments, including SaaS products.

Recommendations For Apache Kafka versions 3.1.0 through 3.9.0, update to version 3.9.1 or later and configure the allowed URLs using the system property -Dorg.apache.kafka.sasl.oauthbearer.allowed.urls. For Apache Kafka version 3.9.1, configure the allowed URLs using the system property -Dorg.apache.kafka.sasl.oauthbearer.allowed.urls to restrict access to sensitive files and locations. For Apache Kafka version 4.0.0 and later, the default value for allowed URLs is an empty list, so users must explicitly set the allowed URLs using the system property -Dorg.apache.kafka.sasl.oauthbearer.allowed.urls.