Sensitive Information in Resource Not Removed Before Reuse in Logstash Leading to Access to Sensitive Information
Dependency on Vulnerable Third-Party Component (CWE-1395) exists in org.lz4:lz4-java decompression library used by logstash-integration-kafka plugin in Logstash that could allow an attacker to access sensitive information from previous buffer contents via Input Data Manipulation (CAPEC-153). Exploitation requires the attacker to produce specially crafted, malformed compressed input to a Kafka topic consumed by Logstash, causing the decompression process to expose residual data from reused output buffers that were not cleared between operations - CVE-2025-66566.
Affected Versions:
- 8.x: All versions from 8.15.0 up to and including 8.19.9
- 9.x:
- All versions from 9.0.0 up to and including 9.1.9
- All versions from 9.2.0 up to and including 9.2.3
Affected Configurations:
This vulnerability is limited to Logstash deployments that have the logstash-integration-kafka plugin configured to consume from a Kafka topic to which the attacker can publish messages. The attacker requires network access to the Kafka cluster and sufficient Kafka-level permissions (e.g., Kafka ACLs, if configured) to publish messages to the target topic.
Solutions and Mitigations:
The issue is resolved in version 8.19.10, 9.1.10, 9.2.4.
For Users that Cannot Upgrade:
The attacker requires network access to the Kafka cluster and sufficient Kafka-level permissions (e.g., Kafka ACLs, if configured) to publish messages to the target topic.
Manually update the logstash-integration-kafka plugin to version 11.8.1 or higher using: bin/logstash-plugin update logstash-integration-kafka
Severity: CVSSv3.1: Medium ( 5.9 ) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CVE ID: CVE-2025-66566
Problem Type: CWE-226 - Sensitive Information in Resource Not Removed Before Reuse
Impact: CAPEC-153 - Input Data Manipulation