CVE-2026-33558CWE-533

Apache Kafka, Apache Kafka Clients: Information Exposure Through Network Client Log Output

Medium · published April 20, 2026

CVSS v3.1
5.3
EPSS
1%
Percentile
48.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00630 · 48.0th percentile
Weakness
CWE-533 · DEPRECATED: Information Exposure Through Server Log Files
Published
2026-04-20T13:20Z
EPSS history
Timeline
  • 20 APR 13:20Z
    Apache Kafka, Apache Kafka Clients: Information Exposure Through Network Client Log Output
    cvelistv5