Executive brief
Spring for Apache Kafka is a library used to integrate Java applications with the Apache Kafka messaging system. A vulnerability in its retry mechanism allows a malicious user to manipulate message headers to disrupt how the system handles failed messages. This can lead to messages being routed incorrectly within the retry sequence, potentially causing processing delays or service instability.
Technical details
A vulnerability exists in Spring for Apache Kafka's retry topic infrastructure due to insufficient validation of user-controlled header values. Specifically, an attacker with the ability to produce records can craft a 'retry_topic-attempts' header with an out-of-range value. This causes the retry topic router to misidentify the message's position in the retry sequence, leading to improper routing or potential denial of service for specific message flows. The issue is rooted in CWE-20 (Improper Input Validation) and has been addressed by hardening the header decoding logic in versions 4.0.6 and 3.3.16.
Affected products
- Spring Spring for Apache Kafka 4.0.0 - 4.0.5, 3.3.0 - 3.3.15, 3.2.0 - 3.2.13, 2.9.0 - 2.9.13, 2.8.0 - 2.8.11
Timeline
- 2026-06-09: patched: Versions 4.0.6 and 3.3.16 released
- 2026-06-10: disclosed: Initial advisory publication
- 2026-08-12: advisory: Advisory updated and reviewed by GitHub