# CVE-2026-41727: VMware Spring Kafka improper input validation in retry topic infrastructure

Source: https://junglewise.ai/threats/cve-2026-41727-vmware-spring-kafka-improper-input-validation-in-retry-topic  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-10. Updated: 2026-08-12  
License: CC BY 4.0 with a link back

CVE-2026-41727 · Severity: medium · CVSS 6.5 · Published 2026-06-10

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.

Technologies: [org.springframework.kafka:spring-kafka (Maven)](https://junglewise.ai/threats/technologies/org-springframework-kafka-spring-kafka), [VMware Spring for Apache Kafka](https://junglewise.ai/threats/technologies/spring-for-apache-kafka). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven), [VMware](https://junglewise.ai/threats/vendors/vmware).

## Quick answers

**Is CVE-2026-41727 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-41727 being exploited in the wild.

**How severe is CVE-2026-41727?** Medium severity, with a CVSS score of 6.5, published 10 June 2026.

**Which products and versions are affected?** org.springframework.kafka:spring-kafka (Maven) ECOSYSTEM:introduced=4.0.0,fixed=4.0.6; VMware Spring for Apache Kafka 4.0.0 through 4.0.5; 3.3.0 through 3.3.15; 3.2.0 through 3.2.13; 2.9.0 through 2.9.13; 2.8.0 through 2.8.11.

**Is there a fix for CVE-2026-41727?** Yes. org.springframework.kafka:spring-kafka (Maven): upgrade to 4.0.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-41727 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-41727?** Check whether you run org.springframework.kafka:spring-kafka (Maven) or VMware Spring for Apache Kafka at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- org.springframework.kafka:spring-kafka (Maven): upgrade to 4.0.6 or later

  ```sh
  # set org.springframework.kafka:spring-kafka to 4.0.6 in your pom.xml or build.gradle
  ```


## 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

## Identifiers

- CVE-2026-41727
- GHSA-53w6-v7cv-fc9h

## 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

## References

- [https://spring.io/security/cve-2026-41727](https://spring.io/security/cve-2026-41727)
- [https://github.com/spring-projects/spring-kafka/releases/tag/v3.3.16](https://github.com/spring-projects/spring-kafka/releases/tag/v3.3.16)
- [https://github.com/spring-projects/spring-kafka/releases/tag/v4.0.6](https://github.com/spring-projects/spring-kafka/releases/tag/v4.0.6)

## Related threats

- [VMware Spring for Apache Kafka deserialization in JsonKafkaHeaderMapper](https://junglewise.ai/threats/cve-2026-41731-vmware-spring-for-apache-kafka-deserialization-in)
- [VMware Spring for Apache Kafka denial of service in DelegatingDeserializer](https://junglewise.ai/threats/cve-2026-41726-vmware-spring-for-apache-kafka-denial-of-service-in)
- [Spring-Kafka has Java Deserialization vulnerability When Improperly Configured](https://junglewise.ai/threats/cve-2023-34040-spring-kafka-has-java-deserialization-vulnerability-when)