Quick answers
- Is CVE-2026-111108 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-111108 being exploited in the wild.
- How severe is CVE-2026-111108?
- Informational severity, published 28 October 2026.
- Which products and versions are affected?
- Apache Kafka.
- Is there a fix for CVE-2026-111108?
- Yes: fixed in Apache Kafka 4.2.2, 4.3.2, or 4.4.0. Until then: Lower the socket.request.max.bytes setting and restrict network access to broker listeners to reduce exposure until upgrading. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-111108 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-111108?
- Check whether you run Apache Kafka. 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
- Fixed in: Apache Kafka 4.2.2, 4.3.2, or 4.4.0
Lower the socket.request.max.bytes setting and restrict network access to broker listeners to reduce exposure until upgrading.
Technical details
The vulnerability exists in Kafka's code-generated protocol message readers, which pre-allocate array collections based on element counts declared by the sender without proper validation. The reader only checks the declared count against remaining buffer bytes, assuming one byte per element; since most elements require multiple bytes, an attacker can declare a far larger count than the buffer contains. For keyed arrays, this triggers allocation of ImplicitLinkedHashCollection with capacity (2 * count + 1), allowing requests of tens of megabytes to force heap allocations several times larger before any element is parsed. Request parsing occurs before authorization checks, enabling exploitation on PLAINTEXT listeners by unauthenticated clients.
Affected products
- Apache Kafka
Timeline
- 2026-10-28: disclosed