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

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Summary

CVECVE-2026-33558
StatePUBLISHED
Assignerapache
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-20 14:16:19 UTC
Updated2026-04-22 14:16:12 UTC
DescriptionInformation 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.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS: 0.000270000 probability, percentile 0.077650000 (date 2026-04-22)

Problem Types: CWE-533 | CWE-533 CWE-533 DEPRECATED: Information Exposure Through Server Log Files

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Apache Kafka All All All All
Application Apache Kafka 4.0.0 - All All
Application Apache Kafka 4.0.0 rc0 All All
Application Apache Kafka 4.0.0 rc1 All All
Application Apache Kafka 4.0.0 rc3 All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apache Software Foundation Apache Kafka affected 0.11.0 3.9.1 semver Not specified
CNA Apache Software Foundation Apache Kafka affected 4.0.0 semver Not specified
CNA Apache Software Foundation Apache Kafka Clients affected 0.11.0 3.9.1 semver Not specified
CNA Apache Software Foundation Apache Kafka Clients affected 4.0.0 semver Not specified

References

ReferenceSourceLinkTags
lists.apache.org/thread/pz5g4ky3h0k91tfd14p0dzqjp80960kl [email protected] lists.apache.org Mitigation, Vendor Advisory
kafka.apache.org/cve-list [email protected] kafka.apache.org Vendor Advisory
www.openwall.com/lists/oss-security/2026/04/17/3 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Alyssa Huang <[email protected]> (en)

CNA: Luke Chen <[email protected]> (en)

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