Re: CVE-2026-35554: Apache Kafka Clients: Kafka Producer Message Corruption and Misrouting via Buffer Pool Race Condition

Hi Manikumar, The CVE seems to be still reserved and not published yet. Best, On Tue, Apr 7, 2026 at 1:49 PM Manikumar <manikumar@apache.org> wrote: > Severity: moderate > > Affected versions: > > - Apache Kafka Clients (org.apache.kafka:kafka-clients) 2.8.0 through 3.9.1 > - Apache Kafka Clients (org.apache.kafka:kafka-clients) 4.0.0 through 4.0.1 > - Apache Kafka Clients (org.apache.kafka:kafka-clients) 4.1.0 through 4.1.1 > > Description: > > A race condition in the Apache Kafka Java producer client’s buffer > pool management can cause messages to be silently delivered to > incorrect topics. > > When a produce batch expires due to delivery.timeout.ms while a > network request containing that batch is still in flight, the batch’s > ByteBuffer is prematurely deallocated and returned to the buffer pool. > If a subsequent producer batch—potentially destined for a different > topic—reuses this freed buffer before the original network request > completes, the buffer contents may become corrupted. This can result > in messages being delivered to unintended topics without any error > being reported to the producer. > > > Data Confidentiality: > Messages intended for one topic may be delivered to a different topic, > potentially exposing sensitive data to consumers who have access to > the destination topic but not the intended source topic. > > Data Integrity: > Consumers on the receiving topic may encounter unexpected or > incompatible messages, leading to deserialization failures, processing > errors, and corrupted downstream data. > > This issue affects Apache Kafka versions ≤ 3.9.1, ≤ 4.0.1, and ≤ 4.1.1. > > Kafka users are advised to upgrade to 3.9.2, 4.0.2, 4.1.2, 4.2.0, or > later to address this vulnerability. > > Credit: > > Bharath Vissapragada <bharathv@apache.org> (reporter) > Donny Nadolny <donny.nadolny@hotmail.com> (finder) > Donny Nadolny <donny.nadolny@hotmail.com> (remediation developer) > > References: > > https://issues.apache.org/jira/browse/KAFKA-19012https://kafka.apache.org/community/cve-listhttps://www.cve.org/CVERecord?id=CVE-2026-35554 > -- [image: Aiven] <https://www.aiven.io> *Josep Prat* Sr. Engineering Director, Streaming Services, *Aiven* josep.prat@aiven.io | +491715557497 aiven.io <https://www.aiven.io> | <https://www.facebook.com/aivencloud> <https://www.linkedin.com/company/aiven/> <https://twitter.com/aiven_io> *Aiven Deutschland GmbH* Alexanderufer 3-7, 10117 Berlin Geschäftsführer: Oskari Saarenmaa, Kenneth Chen Amtsgericht Charlottenburg, HRB 209739 B