Is CVE-2026-59306 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-59306 being exploited in the wild.

How severe is CVE-2026-59306?

Low severity, with a CVSS score of 3.1, published 27 August 2026.

Which products and versions are affected?

Spring Cloud Stream 4.2.0–4.2.6, 4.3.0–4.3.3, 5.0.0–5.0.2.

Is there a fix for CVE-2026-59306?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-59306 attacked?

It is attacked over the network.

Am I affected by CVE-2026-59306?

Check whether you run Spring Cloud Stream 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.

CVE-2026-59306: Spring Cloud Stream deserialization of untrusted types

CVE-2026-59306 · Severity: low · CVSS 3.1 · Published 2026-08-27

Spring Cloud Stream is a framework for building event-driven microservices that process messages from brokers. This vulnerability allows an attacker to exploit unsafe deserialization to execute arbitrary code on systems using affected versions. An attacker with network access to the message broker could inject malicious serialized objects, leading to remote code execution and complete system compromise.

Vendors: Spring.

Quick answers

Is CVE-2026-59306 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-59306 being exploited in the wild.
How severe is CVE-2026-59306?: Low severity, with a CVSS score of 3.1, published 27 August 2026.
Which products and versions are affected?: Spring Cloud Stream 4.2.0–4.2.6, 4.3.0–4.3.3, 5.0.0–5.0.2.
Is there a fix for CVE-2026-59306?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-59306 attacked?: It is attacked over the network.
Am I affected by CVE-2026-59306?: Check whether you run Spring Cloud Stream 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.

Technical details

The vulnerability involves unsafe deserialization of untrusted Java objects within Spring Cloud Stream's message processing pipeline. The root cause is insufficient validation of serialized types before deserialization, allowing an attacker to instantiate arbitrary classes. An attacker with access to the underlying message broker (RabbitMQ, Kafka, etc.) can craft malicious serialized payloads that, when deserialized by the application, execute arbitrary code. The attack vector is network-adjacent, requiring broker access. Patches are available in Spring Cloud Stream 4.2.7+, 4.3.4+, and 5.0.3+.

Affected products

Spring Cloud Stream 4.2.0–4.2.6, 4.3.0–4.3.3, 5.0.0–5.0.2

Timeline

2026-08-27: disclosed

References

https://spring.io/security/cve-2026-59306

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