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Medium

Apache Kafka exposes sensitive information in its DEBUG logs

  • Disclosed: 20.04.2026
  • Updated: 11.10.2026 13:20

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. Apache advises Kafka users to upgrade to v3.9.2, v4.0.1, or later to avoid this vulnerability.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) org.apache.kafka:kafka-clients >= 0.11.0, < 3.9.2, >= 4.0.0, < 4.0.1 3.9.2, 4.0.1

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness (CWE)
CWE-532
Platform
Java / Kotlin (Maven)
Package
org.apache.kafka:kafka-clients
Disclosed
20.04.2026
Updated
11.10.2026 13:20

Sources and licenses

OSV / GitHub Advisory Database - GHSA-wf66-mphr-4c4r - CC BY 4.0

Vulnerability history: org.apache.kafka:kafka-clients

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
7
First → latest
09.2021 04.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • High 1
  • Medium 5

Disclosures per year

  1. Apache Kafka exposes sensitive information in its DEBUG logs this entry
    Medium · 5.3 CVE-2026-33558 >= 0.11.0, < 3.9.2, >= 4.0.0, < 4.0.1 3.9.2, 4.0.1
  2. Apache Kafka does not validate JWT tokens in its OAUTHBEARER authentication implementation
    Critical · 9.1 CVE-2026-33557 >= 4.1.0, < 4.1.2 4.1.2
  3. Apache Kafka Clients: Kafka Producer Message Corruption and Misrouting via Buffer Pool Race Condition
    High · 8.7 CVE-2026-35554 >= 2.8.0, < 3.9.2, >= 4.0.0, < 4.0.2, >= 4.1.0, < 4.1.2 3.9.2, 4.0.2, 4.1.2
  4. Apache Kafka Client Arbitrary File Read and Server Side Request Forgery Vulnerability
    Medium · 7.5 CVE-2025-27817 >= 3.1.0, < 3.9.1 3.9.1
  5. Apache Kafka Clients: Privilege escalation to filesystem read-access via automatic ConfigProvider
    Medium · 6.5 CVE-2024-31141 >= 2.3.0, < 3.7.1 3.7.1
  6. Improper Authentication in Apache Kafka
    Medium · 6.8 CVE-2017-12610 >= 0.10.0.0, < 0.10.2.2, >= 0.11.0.0, < 0.11.0.2 0.10.2.2, 0.11.0.2
  7. Observable Discrepancy in Apache Kafka
    Medium · 5.9 CVE-2021-38153 >= 2.0.0, < 2.6.3, >= 2.7.0, < 2.7.2, >= 2.8.0, < 2.8.1 2.6.3, 2.7.2, 2.8.1

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