High

Apache Kafka Clients: Kafka Producer Message Corruption and Misrouting via Buffer Pool Race Condition

Disclosed: 07.04.2026
Updated: 11.10.2026 13:20

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.

Affected software

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Platform	Package	Vulnerable versions	Fixed in
Java / Kotlin (Maven)	org.apache.kafka:kafka-clients	>= 2.8.0, < 3.9.2, >= 4.0.0, < 4.0.2, >= 4.1.0, < 4.1.2	3.9.2, 4.0.2, 4.1.2

References

CVSS score 8.7/10

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weakness (CWE): CWE-362
Platform: Java / Kotlin (Maven)
Package: org.apache.kafka:kafka-clients
Disclosed: 07.04.2026
Updated: 11.10.2026 13:20

Sources and licenses

OSV / GitHub Advisory Database - GHSA-5qcv-4rpc-jp93 - CC BY 4.0

Vulnerability history: org.apache.kafka:kafka-clients

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries: 7
First → latest: 09.2021 04.2026
Without a fix: 0
Exploited in attacks: 0

Severity breakdown

Critical 1
High 1
Medium 5

Disclosures per year

2021: 1
2022: 1
2023: 0
2024: 1
2025: 1
2026: 3

20.04.2026

Apache Kafka exposes sensitive information in its DEBUG logs

Medium · 5.3 CVE-2026-33558 >= 0.11.0, < 3.9.2, >= 4.0.0, < 4.0.1 3.9.2, 4.0.1
20.04.2026

Apache Kafka does not validate JWT tokens in its OAUTHBEARER authentication implementation

Critical · 9.1 CVE-2026-33557 >= 4.1.0, < 4.1.2 4.1.2
07.04.2026

Apache Kafka Clients: Kafka Producer Message Corruption and Misrouting via Buffer Pool Race Condition this entry

High · 8.7 CVE-2026-35554 >= 2.8.0, < 3.9.2, >= 4.0.0, < 4.0.2, >= 4.1.0, < 4.1.2 3.9.2, 4.0.2, 4.1.2
10.06.2025

Apache Kafka Client Arbitrary File Read and Server Side Request Forgery Vulnerability

Medium · 7.5 CVE-2025-27817 >= 3.1.0, < 3.9.1 3.9.1
19.11.2024

Apache Kafka Clients: Privilege escalation to filesystem read-access via automatic ConfigProvider

Medium · 6.5 CVE-2024-31141 >= 2.3.0, < 3.7.1 3.7.1
13.05.2022

Improper Authentication in Apache Kafka

Medium · 6.8 CVE-2017-12610 >= 0.10.0.0, < 0.10.2.2, >= 0.11.0.0, < 0.11.0.2 0.10.2.2, 0.11.0.2
23.09.2021

Observable Discrepancy in Apache Kafka

Medium · 5.9 CVE-2021-38153 >= 2.0.0, < 2.6.3, >= 2.7.0, < 2.7.2, >= 2.8.0, < 2.8.1 2.6.3, 2.7.2, 2.8.1

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