CVE-2026-33558Network attack vector

Sensitive-data exposure via unredacted DEBUG logging

Published Apr 20, 2026 · Updated Apr 20, 2026

Information disclosure in Apache Kafka 0.11.0 through 3.9.1 and 4.0.0 allows attackers with log access to read secrets from DEBUG output. NetworkClient serializes complete configuration, credential, authentication, and delegation-token requests and responses to logs without redacting sensitive fields. Exposure requires nondefault DEBUG logging for NetworkClient and access to the resulting logs, which can retain authentication and configuration data.

CVSS severity5.3
Medium
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Apache Kafka 0.11.0 through 3.9.1 and 4.0.0 allows attackers with log access to read secrets from DEBUG output. NetworkClient serializes complete configuration, credential, authentication, and delegation-token requests and responses to logs without redacting sensitive fields. Exposure requires nondefault DEBUG logging for NetworkClient and access to the resulting logs, which can retain authentication and configuration data.

The record

CVE
CVE-2026-33558
Published
Apr 20, 2026
Updated
Apr 20, 2026
Vendor
The Apache Software Foundation
Product
Apache Kafka Clients
Classifications
CWE-533, T1552.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.11.0 <=3.9.1
  2. Affected versionversion=4.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Kafka Clientsversion=0.11.0 <=3.9.1; version=4.0.0
The Apache Software Foundation · Apache Kafkaversion=0.11.0 <=3.9.1; version=4.0.0

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-533DEPRECATED: Information Exposure Through Server Log Files
T1552.001Credentials In Files

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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