Severity: important
Affected versions:
- Apache Kafka Client 3.1.0 through 3.9.0
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" configuratin to read arbitrary contents of
the disk and environment variables or make requests to an unintended location.
In particular, 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.
Since Apache Kafka 3.9.1/4.0.0, we have added a system property
("-Dorg.apache.kafka.sasl.oauthbearer.allowed.urls") to set the allowed urls in
SASL JAAS configuration. In 3.9.1, it accepts all urls by default for backward
compatibility. However in 4.0.0 and newer, the default value is empty list and
users have to set the allowed urls explicitly.
Credit:
罗鑫 <lx2317103...@gmail.com> (finder)
1ue (https://github.com/luelueking) (finder)
4ra1n (https://github.com/4ra1n) (finder)
enokiy <846800...@qq.com> (finder)
VulTeam of ThreatBook (finder)
References:
https://kafka.apache.org/
https://www.cve.org/CVERecord?id=CVE-2025-27817
