CVE-2026-33558

Description

Information exposure vulnerability has been identified in Apache Kafka. The NetworkClient component will output entire requests and responses information in the DEBUG log level in the logs. By default, the log level is set to INFO level. If the DEBUG level is enabled, the sensitive information will be exposed via the requests and responses output log. The entire lists of impacted requests and responses are: * AlterConfigsRequest * AlterUserScramCredentialsRequest * ExpireDelegationTokenRequest * IncrementalAlterConfigsRequest * RenewDelegationTokenRequest * SaslAuthenticateRequest * createDelegationTokenResponse * describeDelegationTokenResponse * SaslAuthenticateResponse This issue affects Apache Kafka: from any version supported the listed API above through v3.9.1, v4.0.0. We advise the Kafka users to upgrade to v3.9.2, v4.0.1, or later to avoid this vulnerability.

PUBLISHED Reserved 2026-03-23 | Published 2026-04-20 | Updated 2026-04-20 | Assigner apache

Problem types

CWE-533 DEPRECATED: Information Exposure Through Server Log Files

Product status

Credits

Alyssa Huang <ahuang@confluent.io> finder

Luke Chen <showuon@gmail.com> finder

References

www.openwall.com/lists/oss-security/2026/04/17/3

kafka.apache.org/cve-list vendor-advisory

lists.apache.org/thread/pz5g4ky3h0k91tfd14p0dzqjp80960kl mailing-list

cve.org (CVE-2026-33558)

nvd.nist.gov (CVE-2026-33558)

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