CVE-2026-111108
Description
A flaw was found in Apache Kafka. Due to improper input validation during protocol request parsing, the service pre-allocates disproportionately large memory collections based on the sender's declared array element count without verifying that the request buffer contains sufficient data. A remote attacker can exploit this vulnerability by sending requests specifying excessively large array lengths, forcing substantial memory allocation before authorization checks occur. This excessive allocation can exhaust broker heap memory and crash the service, resulting in a Denial of Service (DoS).
Statement
This flaw is in Apache Kafka broker request parsing: generated protocol readers can pre-allocate large heap collections from an attacker-controlled array length before authorization, enabling out-of-memory denial of service. Red Hat rates it Important for deployments that expose Kafka broker listeners.
Most Red Hat offerings listed against kafka-clients are not affected because they do not run an Apache Kafka broker that accepts Kafka API requests from clients. Quarkus, Camel, Fuse, Debezium, Service Registry, and related cloud-service images use kafka-clients only as producers or consumers against an external cluster. OpenShift Serverless kn-ekb dispatcher/receiver components are a Knative Eventing Kafka data plane (HTTP plus kafka-clients) and are not Kafka brokers, so they are not exposed to this request-parse path. The Red Hat product that remains affected is AMQ Streams, which ships the Kafka broker and falls within the upstream affected version range.
Mitigation
Red Hat is not aware of any available mitigation for this issue. Customers are advised to apply the relevant security updates as they become available.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 9.1 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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