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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

EPSS

• CVE-2026-35554: 0.44% estimated exploitation activity in the next 30 days; percentile 38.00 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

7 Apr 2026, 15:30 UTC

Last modified by the source

13 Apr 2026, 19:22 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-5qcv-4rpc-jp93

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# Patch Next advisory brief: CVE-2026-35554

Advisory: Apache Kafka Clients: Kafka Producer Message Corruption and Misrouting via Buffer Pool Race Condition
IDs: CVE-2026-35554, GHSA-5qcv-4rpc-jp93
Record: https://patchnext.com/advisories/cve-2026-35554 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.apache.kafka:kafka-clients 4.1.2, 4.0.2, 3.9.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.kafka:kafka-clients: affected >= 2.8.0, < 3.9.2; >= 4.0.0, < 4.0.2; >= 4.1.0, < 4.1.2; fixed in 3.9.2, 4.0.2, 4.1.2

## Suggested inspection (read-only)
- Maven org.apache.kafka:kafka-clients: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.apache.kafka:kafka-clients.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-5qcv-4rpc-jp93 (GitHub-reviewed advisory GHSA-5qcv-4rpc-jp93 lists affected ranges: Maven org.apache.kafka:kafka-clients >=2.8.0 =4.0.0 =4.1.0 <4.1.2)

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