Quick answers
- Is CVE-2026-59304 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-59304 being exploited in the wild.
- How severe is CVE-2026-59304?
- Low severity, with a CVSS score of 3.1, published 27 August 2026.
- Which products and versions are affected?
- VMware 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-2026-59304?
- 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-2026-59304 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-59304?
- Check whether you run VMware 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 stems from improper caching of the original content type in Spring Cloud Stream's Avro serialization/deserialization component. The affected versions cache content type information without proper validation or reset mechanisms, allowing the cached value to persist incorrectly across message processing operations. This could enable an attacker on the network to send specially crafted messages that cause the cached content type to diverge from the actual message content type, resulting in incorrect parsing or processing of subsequent messages. The issue affects multiple versions across Spring Cloud Stream 4.2.x, 4.3.x, and 5.0.x release lines.
Affected products
- VMware 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