# CVE-2026-41726: VMware Spring for Apache Kafka denial of service in DelegatingDeserializer

Source: https://junglewise.ai/threats/cve-2026-41726-vmware-spring-for-apache-kafka-denial-of-service-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-10. Updated: 2026-06-12  
License: CC BY 4.0 with a link back

CVE-2026-41726 · Severity: medium · CVSS 6.5 · Published 2026-06-10

A vulnerability in Spring for Apache Kafka can allow an attacker to crash a Java application by exhausting its memory. By sending specially crafted messages with unique headers, an attacker can force the system to store an unlimited amount of data in its internal cache. This leads to severe performance degradation and eventually causes the application to stop responding.

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-2026-41726 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-41726 being exploited in the wild.

**How severe is CVE-2026-41726?** 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-2026-41726?** 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-2026-41726 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-41726?** 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

The vulnerability is a resource exhaustion issue (CWE-770) within the DelegatingDeserializer component of Spring for Apache Kafka. When this component is enabled, it maintains an internal delegate cache that uses the 'spring.kafka.serialization.selector' header value as a key. Because this cache is unbounded, a remote attacker with permissions to produce records can send messages with unique, random selector headers. This causes the heap to grow without limit, leading to excessive Garbage Collection (GC) overhead and an eventual OutOfMemoryError (OOM). Patches are available in versions 4.0.6 and 3.3.16.

## Affected products

- Spring Spring for Apache Kafka 4.0.0 to 4.0.5, 3.3.0 to 3.3.15, 3.2.0 to 3.2.13, 2.9.0 to 2.9.13, 2.8.0 to 2.8.11

## Identifiers

- CVE-2026-41726
- GHSA-xvfq-4q6q-gxx7

## Timeline

- 2026-06-10: disclosed
- 2026-06-10: advisory

## References

- [https://api.github.com/users/julianladisch](https://api.github.com/users/julianladisch)
- [https://github.com/julianladisch](https://github.com/julianladisch)
- [https://api.github.com/users/julianladisch/gists%7B/gist_id%7D](https://api.github.com/users/julianladisch/gists%7B/gist_id%7D)
- [https://api.github.com/users/julianladisch/repos](https://api.github.com/users/julianladisch/repos)
- [https://avatars.githubusercontent.com/u/533612?v=4](https://avatars.githubusercontent.com/u/533612?v=4)
- [https://api.github.com/users/julianladisch/events%7B/privacy%7D](https://api.github.com/users/julianladisch/events%7B/privacy%7D)

## 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 Kafka improper input validation in retry topic infrastructure](https://junglewise.ai/threats/cve-2026-41727-vmware-spring-kafka-improper-input-validation-in-retry-topic)
- [Spring-Kafka has Java Deserialization vulnerability When Improperly Configured](https://junglewise.ai/threats/cve-2023-34040-spring-kafka-has-java-deserialization-vulnerability-when)