CVE-2026-33558

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

MEDIUM
5.3
CVSS Score
Published: April 20, 2026 at 01:20 PM UTC
Updated: June 17, 2026 at 10:37 AM UTC
1 product affected across 1 vendorKafka

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.11.0 ≤ v ≤ 3.9.10.11.0.0 ≤ v < 3.9.20.11.04.0.04.0.0 rc04.0.0 rc14.0.0 rc3

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

Vendor Advisory
Source: cverecord
https://kafka.apache.org/cve-list
Mailing ListMitigationVendor Advisory
Source: cverecord
https://lists.apache.org/thread/pz5g4ky3h0k91tfd14p0dzqjp80960kl
Mailing List
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/04/17/3

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-533

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