Apache Kafka up to 4.2.1/4.3.1 Admin REST API /admin/loggers improper authorization

Summaryinfo

A vulnerability has been found in Apache Kafka up to 4.2.1/4.3.1 and classified as critical. Affected is an unknown function of the file /admin/loggers of the component Admin REST API. This manipulation causes improper authorization. This vulnerability appears as CVE-2026-115644. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in Apache Kafka up to 4.2.1/4.3.1 and classified as critical. Affected by this vulnerability is an unknown part of the file /admin/loggers of the component Admin REST API. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Apache Kafka Connect contains an authentication bypass vulnerability affecting the admin REST API when admin.listeners is configured with a separate listener from the main listeners property. When operators isolate the admin REST API by explicitly configuring the "admin.listeners" property, REST extensions specified via rest.extension.classes (such as BasicAuthSecurityRestExtension) are not registered or applied to the admin resource configuration. While the primary REST API listener (configured via listeners) enforces configured authentication and authorization filters, endpoints mounted under the separate admin listener (/admin/loggers) fail to inherit or instantiate these extension filters. As a result, the admin logger endpoint accepts unauthenticated read and write requests even when security extensions are active on the main listener. Impact: An unauthenticated attacker with network access to the admin listener can: 1. Read the complete set of logger names and levels, disclosing loaded class names and which security extensions are in use. 2. Write logger levels, including with scope=cluster which propagates the change to all workers in the Connect cluster. This can be used to suppress logging (setting root to OFF) or generate excessive log output (setting root to TRACE), potentially impacting availability and observability. Mitigation: Users who cannot upgrade immediately can remove the admin.listeners configuration (or leave it unset). When unset, admin resources share the regular listener and inherit its security extensions. Resolution: From Apache Kafka 4.2.2, 4.3.2, and 4.4.0, we make sure the REST extensions specified via "rest.extension.classes" will also apply to "admin.listeners".

The advisory is shared at kafka.apache.org. This vulnerability is known as CVE-2026-115644 since 10/23/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/28/2026). MITRE ATT&CK project uses the attack technique T1548.002 for this issue.

Upgrading to version 4.2.2, 4.3.2 or 4.4.0 eliminates this vulnerability.

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Productinfo

Vendor

• Apache

Name

• Kafka

Version

• 4.2.0
• 4.2.1
• 4.3.0
• 4.3.1

License

• open-source

Website

• Vendor: https://www.apache.org/

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